Related Companies

AFC-HolcroftWhen it comes to thermal processing equipment, AFC-Holcroft has one of the most diversified product lines in the heat treat equipment industry. We are fully equipped to design, manufacture, ship, install, and service all types of custom and standard heat treat systems. We've been making high quality thermal processing equpiment since 1916. Find out why some of the best-known names in manufacturing trust AFC-Holcroft equipment for their production. ISO 9001:2008 certified.

Ajax TOCCO MagnethermicAjax TOCCO induction heat treating systems are being used successfully throughout the world for hardening, annealing, stress relieving, tempering, brazing, bonding, shrink fitting, and many other processes requiring fast, efficient, economical heating. These processes are being applied to virtually any shape of part ranging in size from fractions of an inch to substantial lengths and diameters. With more than 90 years of technical development and experience, Ajax TOCCO analyzes customer’s requirements to provide reliable, efficient, and cost effective solutions to meet their needs.

Applied ProcessApplied Process is a world leader in austempering technology.

Barber-Colman, Div of Bourn & KochBourn & Koch designs and builds new machines for hobbing, grinding, turning and shaping. We also provide parts and service for legacy machine tool products, including Barber-Colman, Fellows and many others.

Bourn & Koch Inc.Established in 1974, Bourn & Koch Inc. is a manufacturer of industrial machine tools for a wide variety of industries. Bourn & Koch Inc. expanded in the new machine market by purchasing Barber-Colman Machine Tool Division in 1985, by purchasing Fellows and Roto-Technology in 2002, and by purchasing DeVlieg Bullard in 2004.

Comtorgage CorporationComtorgage Corporation manufactures a variety of hand-held, indicating gages (analog or digital) designed and built to measure various characteristics of machined, molded, forged, and pressed parts. Comtorgages are intended for use on the shop floor, or in the lab, wherever there is a requirement for frequent, and accurate monitoring of specific dimensions, with or without data collection.

ECM USAECM Technologies started manufacturing heat-treatment furnaces in 1928. Since that time, ECM personnel have always been completely committed to extending their knowledge in the field of temperature control, high pressures, vacuum and the behavior of materials. This expertise, on an industrial scale, has always been enriched by our close partnership with furnace users, engineers, heat treat engineers and developers. Today, our knowledge base is at the core of all our customers' production lines. It is this concern for caring and listening, combined with our passion for our profession, which has forged ECM Technology and ECM USA’s recognized spirit of innovation.

Erwin Junker Machinery, Inc.The JUNKER Group is a global leader in the market for high-speed CBN grinding machines. Since 50 years the JUNKER group has been driven by the belief in the constant improvement of grinding solutions. From individual machines to complete production lines, we offer solutions to suit our customers’ needs in nearly every area of precision grinding.
We have the right machine for any grinding task: Double disc grinding machines, hard turning/grinding machines, profile grinding machines, flute grinding machines, cylindrical grinding machines, cutting tool grinding machines, tool grinding machines, centerless grinding machines, non-circular grinding machines.
Moreover, JUNKER boasts comprehensive references for the engineering and implementation of production lines as well as for the development of customized grinding machines, specially tailored to customers’ grinding needs.

ForkardtGears extend across all industries. Forkardt, for many years, has provided workholding solutions to the gear industry. Applications we have designed workholding for in the gear industry are hard turning, grinding, and creation of pin plate for holding bevel gears

Framo Morat, Inc.Your idea - Our drive
Framo Morat has been producing gears, worm gear sets, and drive solutions for over 100 years. Originating in the "Gear Valley" area of the Black Forest region, they are proudly "Made in Germany". In addition to our standard product lines, we design and implement a wide variety of custom plastic injection molded technical parts and customized drive solutions. Our comprehensive product range covers a broad range of applications. Founding Framo Morat, Inc. in the US is a major milestone as we feel being close to our customers is important. Our company‘s commitment to service includes everything from development and design engineering, to production, installation, and after-sales support. We are your reliable and experienced partner for each stage.

Frenco GmbHFRENCO GmbH was founded in 1978 and has since then been engaged in the special field of gear and spline metrology. Most of today’s gears and splines are precision items, for whose production both know-how and special tools with very tight tolerances are required. In order to inspect the manufactured workpieces, companies need even more accurate measuring and inspection equipment. FRENCO has committed itself to this challenge.

FZGThe Gear Research Centre (FZG) is an integral part of the Faculty of Mechanical Engineering at Technische Universität München in Germany. Founded in 1951 by Prof. Dr.-Ing. E.h. Gustav Niemann, FZG now occupies a leading position in research, development and standardisation as the international competence centre for issues concerning mechanical drive technology. Since 2011 the institute is being led by Prof. Dr.-Ing. K. Stahl, following his precedessor Prof. Dr.-Ing. B.-R. Höhn.

Gear Resource Technologies Inc.Gear Resource Technologies, Inc. (GRT) has focused directly upon precision tooling needs of gear manufacturers, since 1997. We provide a highly-responsive engineering, analytical, and manufacturing resource, for the many specific tooling needs of the industry.

Gleason CorporationGleason Corporation’s mission is to be The Total Gear Solutions Provider™ to its global customer base. Gleason is a world leader in the development, manufacture and sale of gear production machinery and related equipment. The Company’s products are used by customers in automotive, truck, aircraft, agriculture, mining, windpower, construction, power tool and marine industries and by a diverse set of customers serving various industrial equipment markets. Gleason has manufacturing operations in Rochester, New York; Rockford, Illinois; Dayton, Ohio; Munich and Ludwigsburg, Germany; Studen, Switzerland; Bangalore; India, and Suzhou, China and has sales and service offices throughout North and South America, Europe and in the Asia-Pacific region.

Gleason Cutting Tools CorporationWherever superior gear performance is needed -- from hand-held power tools to super tankers, from automobiles to aircraft -- Gleason Cutting Tools Corporation gear tools are at work, helping raise the standard of bevel and cylindrical gear manufacturing to levels unimaginable just a few years ago.

Hainbuch AmericaFor over 60 years HAINBUCH has been constantly developing new gear clamping solutions focusing on the essentials: the wants and needs of the customer. Set-up times and cost savings, flexibility, productivity, energy efficiency and security – all that you expect from gear clamping solutions.
At HAINBUCH America people don´t just work together, we are one big family. Passion, family spirit and the drive for the right innovation at the right time, that´s the mix that makes HAINBUCH America.

IMT Forge Group including Clifford-Jacobs ForgeThe IMT Forge Group provides world-class, seamlessly integrated, single source closed-die forging services to customers across North America and around the world. Capacities range from ½ pound up to 800 pounds. Advanced machining, heat treatment and surfacing expertise is provided through our IMT sister companies in the Machining Group.
Our three strategically located forging facilities include: Clifford-Jacobs, Welland Forge and PC Forge.

Inductoheat Inc.Inductoheat is the largest global manufacturer of induction heating equipment. We are part of the Inductotherm Group of some 40 companies worldwide. We design & build heat treating equipment & power supplies for heating a wide range of parts including gears & sprockets.

Involute Simulation Softwares Inc.Involute Simulation Softwares specializes in the development of gear calculation and manufacturing software. The main product, HyGEARS™ V 4.0, offers gear designers and manufacturers a standalone software package providing all the design, analysis and manufacturing tools needed from idea to production.

Kapp TechnologiesFor over 50 years, KAPP GmbH has been one of the world's premier manufacturers of machine tools for the precision finishing of gears.

Kapp-Niles IndiaThe KAPP Group offers innovative technologies and systems for high precision hard finishing of gears and profiles. Beginning in 1926 with the development of NILES generating grinding technology for manufacturing high precision gears, NILES quickly became one of the world's leading manufacturers of gear grinding machines.

KISSsoft USA LLCThe KISSsoft calculation program has been developed to focus on the needs of mechanical engineers and power transmission profes

KLINGELNBERG GmbHKlingelnberg is a world leader in the development, manufacture and sale of gear production machinery and related equipment.

KLINGELNBERG India Pvt. Ltd.The Klingelnberg Group is a world leader in the development, manufacture and sale of machines for bevel gear and cylindrical gear production, measuring centers for gearing and axially symmetrical components as well as customized high-precision gear components.

Liebherr America Liebherr Gear Technology Co. is your North American access point to a
broad range of technically advanced gear manufacturing technologies and processes.

Mitsubishi Heavy Industries AmericaOur family of gear cutting machines shares a name and a whole lot more. Mitsubishi gear hobbers, shapers, shavers and grinders also share Mitsubishi machine construction and Mitsubishi software and have common controls. That is why only Mitsubishi gear machines--the most complete family of gear machines--can deliver the fastest CNC learning curves and the highest quality gears.

Nachi America Inc.Nachi Machining Technology Co. is a world leader in the design and manufacture of broaching, cutting, hobbing, shaving, and roll forming machines and tools. In 1991, the Nachi Fujikoshi Corporation of Japan acquired the renowned National Broach and Machine Company, along with the famous Red Ring trade name of high precision tools and machines.

Norton | Saint-GobainNorton, a brand of Saint-Gobain, is a leading manufacturer of a wide array of abrasive products. For applications ranging from rapid stock removal to precision finishing in all industries, products are offered in BEST, BETTER and GOOD performance/price tiers to meet the needs of all end-user applications.

Pentagear ProductsPentagear, a builder of special machines and automated systems for over 50 years, offers the ND430 Next Dimension® Gear Measurement System. The Next Dimension® has been designed with the latest in motion control technology.

Presrite CorporationPresrite manufactures net and near-net forgings for a wide range of industries in countries around the world. Its parts are used in the transmissions, engines and undercarriages of track-type tractors, excavators, wheel loaders and other off-highway vehicles. Presrite institutes an internal program designed to increase performance and quality levels while better controlling costs. Called ?6 SIGMA,? the program involves setting goals, collecting data, and then measuring and analyzing the results.

R.E. Smith & Co., Inc.Over 60 years experience in the gear industry. Over 20 years consulting experience in all types of industries. Over 140 different clients with applications from tiny camera gears to large hydro-electric plant drive gears. We have published numerous articles and technical papers in the area of gear metrology, noise, and transmission error (single flank composite) testing.

Samputensili S.p.A.SU America is a unit of Samputensili S.p.A. of Bologna, Italy and a part of the multi-national Maccaferri Industrial Group.

Seco Tools Inc.Our business mission is to develop, manufacture and globally market metal cutting solutions that satisfy our customer requirements for quality, service and cost-efficiency. Our product portfolio consists of solutions for milling, turning, holemaking and holding systems. We also offer a range of complementary services within the Seco Tools Business Solutions concept.

Solar AtmospheresSolar Atmospheres specializes in vacuum heat treating, vacuum nitriding, vacuum brazing as well as vacuum carburizing services. With processing expertise and personalized service, Solar will process your small or large parts efficiently with our unique range of 40 vacuum furnaces. Sizes range from lab furnaces to the world's largest commercial vacuum furnace.

Star Cutter Co.Headquartered in Farmington Hills, MI, StarCut Sales, Inc. is a wholly owned subsidiary of Star Cutter Company and is a partner in the Star SU LLC enterprise for marketing, sales, and service. Through Star SU and StarCut Sales, Inc.'s international organization Star Cutter Company markets and services its products in North America, South America, Europe and the Far East.

Star SU LLCSU America is a unit of Samputensili S.p.A. of Bologna, Italy and a part of the multinational Maccaferri Industrial Group of companies. Samputensili produces machines, tools and services for the gear manufacturing industry. Manufacturing facilities are located in Italy, France, Brazil, Korea, Japan and the United States.

Tianjin No.1 Machine Tool WorksIn China, Tianjin No.1 Machine Tool Works (TMTW), with a history of 54 years, is one of the large scale manufacturers for gear cutting machines.

Willman Industries Inc.Over the years, Willman Industries Inc. has continued to invest in expansion, better equipment and physical resources in an effort to expand capabilities, increase productivity and to meet the unique needs of our customers

YIEH CHEN MACHINERYYieh Chen Machinery Co., Ltd is the affiliate of Six Star Group. Six Star was founded in 1975 by Six brothers and devoted to the manufacturing of precision gear products. Throughout these years, Six Star has become one of the Top Five gear manufacturers in Taiwan. With a focus on precision gears and gearboxes, Six Star offers a broad range of industries, including machine tools, aerospace, agriculture machinery, robotic arms, transmission, hydraulic pumps and industrial machines.

ZOLLER Inc. Enthusiasm for inspection and measuring technology, a keen sense of efficiency and consequent commitment to quality have assured ZOLLER's position in the world's top league.
Alfred Zoller founded the company in 1945. His vision: cost-efficient manufacturing in cutting production. Eberhard Zoller developed the company further to become a leader in innovation and quality in the measuring sector – and to become a global player. Today, the 3rd generation continues the ZOLLER success story – worldwide. The ZOLLER company has successfully established subsidiaries in the growth markets USA, China, India and Japan.

ZRIMELocated in Zhengzhou, the capital of Henan Province, Zhengzhou Research Institute of Mechanical Engineering (ZRIME) has undergone 50 years of development. The company was restructured from a former research institute under the Ministry of Mechanical Industry into a large-scale science & technology enterprise administered by the central government of China

Related Power Transmission Companies

Arrow Gear Co.Since its inception in 1947, Arrow Gear Company has continued to build a solid reputation for quality, service and reliability. From the very beginning, Arrow has provided high precision spur, helical and bevel gears that meet the rapidly changing and the demanding requirements of many industries.

ATA Gears Ltd.ATA sells, designs and produces spiral bevel gears in the range of 50-3000 mm for demanding marine and industrial applications. ATA serves the customers worldwide.
As a forerunner, ATA maintains a constant motion in developing our know-how, methods and services. ATA has recently been investing heavily in modern production technology and focusing on increasing capacity especially in large spiral bevel gears.

BRECOflex CO., L.L.C.BRECOflex CO., L.L.C. ? The world leader in the polyurethane timing belt industry sets higher standards with new state-of-the-art products. BRECOflex timing belts, pulleys and accessories are scientifically designed and manufactured for undeviatin...

C&U Americas, LLCC&U Bearings are used by some of the world’s leading manufacturers and service providers in a wide variety of applications. Every C&U Bearing is made to exacting standards to deliver the ultimate in the precision, performance, and quality.

Cabat Inc.Cabat Inc is located in Racine Wisconsin and manufactures a varity of overload/torque limiting release clutches.

CENTA Corp.Global leader in the innovation and manufacture of flexible couplings, torsional couplings, and drive shaft solutions for marine and industrial applications.

Framo Morat Inc.Your idea - Our drive
Framo Morat has been producing gears, worm gear sets, and drive solutions for over 100 years. Originating in the "Gear Valley" area of the Black Forest region, they are proudly "Made in Germany". In addition to our standard product lines, we design and implement a wide variety of custom plastic injection molded technical parts and customized drive solutions. Our comprehensive product range covers a broad range of applications. Founding Framo Morat, Inc. in the US is a major milestone as we feel being close to our customers is important. Our company‘s commitment to service includes everything from development and design engineering, to production, installation, and after-sales support. We are your reliable and experienced partner for each stage.

Hangzhou Xingda Machinery Co. Ltd.ounded in 1984, Hangzhou xingda machinery co.,ltd specialized in the development, manufacture and sales of machanic products. The factory has more than 33000 square meters workshop, and with more than 100 sets of advanced process machines and test equipments. Our main produces SPEED REDUCER E-RV worm speed reducer,passed the ISO 9001, are sold to more than hundreds of cities all over the world,both at home and abroad, in area of food industries, Kitchen word machinery, printing machinery, woodworking machinery, small textile machinery, rubber machinery, small chemical machinery, plastic machinery etc.

IDC SelectTo compete in today’s global marketplace, you need a supplier who can provide power transmission products that meet your quality, cost, and delivery requirements. That is why you rely on IDC Select.
We partner with first-rate manufacturers to ensure that we offer you the best possible products. Their product engineers are highly-trained and determined to give you the best experience possible.
IDC Select has the ability to customize our products to fit your specific needs. In most cases, we are able to machine our products to the dimensions that you require. Contact IDC Select at info@IDC-USA.com for questions or with special requests.

Kamar IndustriesKamar Industries manufactures gear products. Small quantity gear orders and quick lead times available in addition to production lot runs. We serve a diverse cross section of industry sectors with metal and plastic gears to satisfy each application.

KTR CorporationKTR Corporation is a wholly owned and operated subsidiary of KTR Kupplungstechnik, GmbH with over 40 subsidiary companies in 21 countries. Our extensive product line began over 50 years ago with the BoWex curved tooth gear coupling and the ROTEX torsionally flexible jaw coupling.
KTR Corporation’s technological strength and innovative problem-solving have earned them prestigious design awards. We manufacture to AGMA and DIN standards to meet the exacting demands of the marketplace. Manufacturing is performed on state-of-the-art CNC machinery to ensure the highest grade components.
KTR Corporation provides superior products and technical service at the lowest possible cost to their customers.

Lafert North AmericaYour best source for Metric Motors, Gearboxes and Coolant pumps, by providing quality products with the highest level of service in the industry.

Luoyang SBI Special Bearing Co. Ltd.With highly advanced technology, Luoyang SBI Special Bearing Co., Ltd. has been dedicated to providing a wide variety of bearing solutions for industries all around the world since its establishment in 1989.

Midwest Gear & Tool, Inc.With more than 20 years in gear manufacturing, Midwest Gear & Tool has an elaborate straight and spiral bevel gear manufacturing capability. We also manufacture a complete line of hydraulic, electric and manual transmissions and reducers.
We m...

Miki Pulley USMiki Pulley offers design solutions for a wide range of motion control applications. Our global network of manufacturing facilities and sales/distribution offices ensure prompt and reliable technical assistance in the U.S. and around the world. Miki Pulley collaborates with design engineers to identify the most cost effective solutions for motion control and mechatronic applications.

New Power Electric (USA) LLCWhatever your needs in variable speed applications, you can trust our 200/300/400/500 series PMDC motors. Designed and built under the highest quality process for general industrial needs, our products are there to provide reliable performance for a long time.

Ningbo Zhongyi Hydraulic Motor Co. Ltd.Ningbo Zhongyi Hydraulic Motor Co., Ltd. was founded in 1971, and is one of the largest hi-tech enterprises in China that specializes in production of hydraulic motors.

NSK CorporationNSK is a global manufacturer of bearings and other motion & control products. It operates 51 manufacturing facilities worldwide and 12 global technology centers of excellence that draw from world-leading industry knowledge and manufacturing experience. NSK's dedication to engineering innovation results in state-of-the-art products designed to improve performance and extend service life. NSK's unique Asset Improvement Program helps customers improve productivity and efficiency to significantly reduce operating costs. The company’s industry and process-specific expertise and solutions are applied to identify and solve problems that are limiting productivity. This enables customers to achieve improved performance, enhanced competitiveness and increased profitability.

PrecipartWe're building solutions to critical motion control specifications every day. That's because custom speedreducers and gearmotors from 7mm diameter and larger are our specialty. And our profound knowledge of materials and gear manufacturing gives youan edge. From our engineering expertise to prototype and production runs, we work in a wide range of industries, including the aerospace/avionics, scientific instrumentation and medical diagnostic and clinical equipment markets.

PSL of AmericaPSL is a European rolling bearing manufacturer with a rich 60 year tradition designing and manfacturing bearings. The company offers a wide range of rolling bearings and slew drive systems.
Teams of professionals with a large breadth of experience covering many manufacturing sectors around the world offer competitive, efficient and innovative solutions to the most demanding engineering and technological challenges. PSL bearings are used in a wide range of applications working in harsh operating conditions where an emphasis is placed on "Quality for Heavy Duty".
PSL can offer several product lines of very precise bearings designed to satisfy all of our customer's needs. Call today so we can help solve your bearing design and manufaturing challenges.

QA1 Precision ProductsQA1 designs, manufactures and distributes rod ends, spherical bearings, performance shock absorbers, struts, springs, and related items. QA1 engineers products that are utilized in a wide variety of industries such as performance racing, off-road recreational vehicles, fitness equipment, packaging equipment, etc.
We are also very experienced in value-added global sourcing for our large OEM customers — we routinely supply major companies with forged, cast, fabricated or machined suspension and driveline components. QA1's quality system is certified to the ISO 9001:2008 standard.

R+W AmericaOver the past 20+ years R+W has developed into a world leader in precision shaft couplings for torsional rigidity, vibration damping, and overload protection. Whether for micro motors or 10 megawatt drives, R+W couplings are customizable for most applications, while many standard models ship from stock. Configurable CAD models are available in a large number of file formats at www.rw-america.com

Randall Publications LLCPublishers of Gear Technology and Power Transmission Engineering magazines, as well as the websites www.powertransmission.com and www.geartechnology.com.

Rave Gears LLCSpiral bevel and hypoid gears from design to doorstep in as little as five weeks. Our brand new, state-of-the-art facility is AS9100 certified, producing the highest quality gears for aerospace, auto racing and other high precision markets.

Ronson Gears Pty. Ltd.Established in 1954 Ronson Gears, is your English speaking and English thinking Asia-Pacific alternative for Precision Gears and Gear Assemblies. Doing business internationally for almost 60 years, Ronson Gears has garnered a reputation for quality, delivery and first-class customer service.

RotekRotek Incorporated, a ThyssenKrupp company and member of the ThyssenKrupp Rothe Erde group, is the North American leading manufacturer of slewing bearings (including ball and roller slewing bearings and wire-race slewing bearings). Furthermore, Rotek is a market leader for seamless forged steel and non-ferrous metal rings.
Throughout the world, Rotek slewing bearings and forged rings are installed in a wide variety of applications. Rotek slewing bearings and forged rings prove every day to be important structural and connection elements used in mechanical engineering, in harbor cranes, ship deck cranes, truck cranes and construction cranes as well as in excavators, antenna systems, in aviation and aerospace, in the offshore technology, rail vehicles, telescopes, tunneling machines, wind energy turbines, underwater turbines and solar energy plants.
ISO 9001, 14001 and 18001 certified. ABS certified.

Schaeffler Group USA, IncSchaeffler North America is responsible for the engineering, production, sales and marketing for the INA, LuK, FAG and Barden brands throughout the United States, Canada, Mexico, Central America and the Caribbean. All four brands provide high-performance, precision technologies for the Automotive OEM, Industrial OEM and Distribution markets as well as the Aerospace industry.
INA is a leading supplier of rolling bearings, linear motion, engine components, plain bearings and precision components.
LuK is a key source for automotive clutch, torque converter, hydraulic and transmission systems.
FAG is a major global supplier of bearings with core competencies in ball, taper, cylindrical and spherical bearing products.
The Barden Corporation focuses on high precision, miniature and aerospace products.

Sesame Motor Corp.Sesame Motor Corporation was founded in 1990 as a manufacturer of motors and gear reducers in Taiwan with its efforts and innovation to obtain compliment and constant growth. Sesame Motor uses world class manufacturing and Enterprise Resource Planning system to build AC/DC motors and precision gear reducers in new factory built in 2009 to be one of the leading makers in motor and gear driving industry.

Techtop Industries, Inc.TECHTOP INDUSTRIES is a manufacturer of high quality AC Electric Motors. TECHTOP's product line covers a wide range of motors from NEMA Premium, High slip, JM/JP Pump, Crusher Duty, IEE 841, Metric IEC, Fractional, Farm Duty and more. TECHTOP strives to create the "best" motor for our customers. Dual oversized bearings, automatic grease purge, brass sintered breather, VPI lap wound stator, and double lip oil seals are just some of the ways TECHTOP has gone the extra mile to over engineer the areas that need it most. Custom motors are also welcome as TECHTOP is outfitted with a full service modification shop.

Yieh Chen Machinery(Six Star Group)[AS9100 certified precision gear manufacturer.] Yieh Chen Machinery Co., Ltd is the affiliate of Six Star Group. Six Star was founded in 1975 by Six brothers and devoted to the manufacturing of precision gear products. Throughout these years, Six Star has become one of the Top Five gear manufacturers in Taiwan. With a focus on precision gears and gearboxes, Six Star offers a broad range of industries, including machine tools, aerospace, agriculture machinery, robotic arms, transmission, hydraulic pumps and industrial machines.
Six Star already received AS 9100 certification for stricter aerospace quality standards, and is also a member of the American Gear Manufacturers Association (AGMA). By paying close attention to every aspect of the gears and gearboxes produced—including profile, lead, pitch, run out, and efficiency—and using measuring facilities, Six Star can ensure that the gears we produce will meet or exceed international standards.
Yieh Chen is never slackening off on pursuing being the best in the global market. Hence, we wish to achieve higher customer satisfaction and build closer relationship with customers by advancing our quality level.

ZRIMELocated in Zhengzhou, the capital of Henan Province, Zhengzhou Research Institute of Mechanical Engineering (ZRIME) has undergone 50 years of development. The company was restructured from a former research institute under the Ministry of Mechanical Industry into a large-scale science & technology enterprise administered by the central government of China.

Articles About M

Last month I attended a meeting in Mexico City sponsored by CIATEQ, a quasi-governmental organization in Mexico, which has as one of its aims the encouragement of the growth of the gear industry in Mexico. The purpose of the meeting was to provide a catalyst among the attendees to form a Mexican equivalent of AGMA and to encourage an alliance with AGMA. Joe Franklin, the Executive Director of AGMA, Bill Boggess, the President, Vice-President Ray Haley, and I were among the few Americans at the meeting.

AGMA and members of the Metal Powder Industries Federation (MPIF) are three years into a joint project to develop specifications and an information sheet on rating powder metal gears. According to committee vice chairman Glen A. Moore of Burgess-Norton Mfg. Co., the first phase of the project, the publication of AGMA Standard "6009-AXX, Specifications for Powder Metallurgy Gears," should be completed in late 1996 or early 1997.

The powder metal (P/M) process is making inroads in automotive transmission applications due to substantially lower costs of P/M-steel components for high-volume production, as compared to wrought or forged steel parts. Although P/M gears are increasingly used in powered hand tools, gear pumps and as accessory components in automotive transmissions, P/M-steel gears are currently in
limited use in vehicle transmission applications. The primary objective of this project was to develop high-strength P/M-steel gears with bending fatigue, impact resistance and pitting fatigue performance
equivalent to current wrought steel gears.

Manufacturing is a hot topic everywhere
these days, what with economic
stimulus plans targeting the struggling
industry worldwide. Many hopes are tied to a manufacturing recovery to bring us further up out of the economic doldrums of 2007–2008. Most indicators show that manufacturing is climbing back, so what better time for the International Manufacturing Technology Show (IMTS) 2010 to witness first hand the next generation’s technology.

September 3-11 the 1986 International Machine Tool Show, "The World of Manufacturing Technology", will be held at the McCormick Place Exposition Center in Chicago. More that 1000 exhibits from over thirty countries are planned. These exhibits will present a complete range of machine-tool products from 2-story high presses to complete manufacturing systems, lathes, lasers, CAD/CAM systems and robotics.

I lost a good friend in October—one that many of you might know. Carlo Costi of Sogimex S.A.S. in Caponago (Milano), Italy, came out of the EMO show in Milan on October 28, caught a taxi and called his wife, Mariella, to tell her that he wasn’t feeling well. He died—in the taxi—on the phone—talking to his wife. He was 60 years old.

In 1993, M & M Precision Systems was awarded a three-year, partial grant from the Advanced Technology Program of the Department of Commerce's National Institute of Standards and Technology (NIST). Working with Pennsylvania State University, M&M embarked on a technology development project to advance gear measurement capabilities to levels of accuracy never before achieved.

The American Gear Manufacturers Association (AGMA) is accredited by the American National Standards Institute (ANSI) to write all U.S. standards on gearing. However, in response to the growing interest in a global marketplace, AGMA became involved with the International Standards Organization (ISO) several years ago, first as an observer in the late 1970s and then as a participant, starting in the early 1980s. In 1993, AGMA became Secretariat (or administrator) for Technical Committee 60 of ISO, which administers ISO gear standards development.

IMTS-90 - the Western Hemisphere's largest trade show - is coming to Chicago September 5 -13, 1990. The event, sponsored by NMTBA - The Association For Manufacturing Technology - will be held at the McCormick Place Complex. Over 1200 exhibitors will display their products at this event.

The Society of Manufacturing Engineers (SME) has been gathering, validating and sharing manufacturing knowledge for more than 80 years. Traditionally, SME resources were purchased by individuals for their own personal use or by colleges and universities as textbooks. Recently, these same colleges and universities were looking for digital resources to provide to their instructors and students. Companies were requesting SME content digitally for their employees as well.

IMTS 92 - The International Manufacturing Technology Show - opens in Chicago September 9 and runs through September 17 at Chicago's McCormick Place. IMTS is the Western Hemisphere's larges trade show. Over 800 companies from all over the globe will be showing products in exhibits covering some 931,000 sq. ft. of space.

The world is full of acronyms. At work, the inbox reveals e-mails from the AWEA, SAE, MPIF and AMT. On the weekends, Saturday mornings are consumed by activities involving the AYSO, PTA, YMCA or DMV. It’s a struggle to determine what organization does what and why we should care in the first
place.

A large number of technologies aimed primarily at higher productivity
were presented by exhibitors at the AMB, International Exhibition for Metal Working at the Stuttgart Trade Fair Centre in September. Following the successful 2010 show, AMB 2012
boasted further developments in energy and resource efficiency, higher productivity, life cycle performance, quality assurance and user-friendliness.

The machine tool industry is as competitive as ever. New machine technologies, materials, coatings and software upgrades are changing the way gears are being manufactured. Companies like Gleason, Liebherr, Kapp/Niles and DMG/Mori Seiki spend plenty of time and resources on R&D to develop the best products for the gear market. More importantly, these companies engage with (and listen to) customer requests.

With 86,202 visitors, The International Exhibition for Metal Working (AMB 2010) in Stuttgart, Germany, managed to slightly exceed attendance from the 2008 show (85,143). The metalworking industry celebrated its comeback
with visitors from more than 80 countries. In addition, AMB 2010 set a new record with 1,346 exhibitors (2008:
1,306).

The International Manufacturing Technology Show provided one of the biggest ever marketplaces for buying and selling gear-making equipment, with 121601 attenders, making it the largest IMTS ever. The show took place September 4-11 at McCormick Place in Chicago, IL.

Gears are currently run at high speed and under high load. It is a significant problem to develop lubricants and gears with high load-carrying capacity against scoring. The particles of molybdenum disulfide have been considered to increase the scoring resistance of the gears. The wear characteristics and the scoring resistance of the gears lubricated with MoS2 paste and MoS2 powder have been investigated. (1) However, there are few investigations on the performance of the gears coated with MoS2 film with respect to scoring.

The AGMA/ABMA Annual Meeting took place April 10-12 in St. Petersburg, Florida. Between committee meetings, networking opportunities and social events, many individuals in the gear industry were presented awards.

Metalworking technology specialists will be front and center for six days at EMO Hannover 2011 (September 19–24). More than 2,000 companies from 38 countries will be on-hand to show off products and services, spotlighting
their performance capabilities.

For two days in Saline, Michigan,
Liebherr's clients, customers and
friends came together to discuss the latest gear products and technology. Peter Wiedemann, president of Liebherr Gear Technology Inc., along with Dr.-Ing. Alois Mundt, managing director, Dr.-Ing. Oliver Winkel, head of application technology, and Dr.-Ing. Andreas Mehr, technology development shaping and grinding, hosted a variety of informative presentations.

Over the past decade, the wire electrical discharge machine (EDM) has become an increasingly important tool for machining non-standard shapes. It has even been used to cut gears and gear cavities for plastic molds. While generally accepted as a quick and versatile method for cutting spur gears, the EDM gear has lacked the precision of a mechanically machined or ground gear. We suspected that many of the errors associated with these gears were caused by inexact setup procedures, poor tool path control and improper cutting parameters. We decided to test the potential for the wire EDM to make the most accurate gear possible.

In 1927 the first precursor of IMTS was held in Cleveland. Back then, lasers, robots and computer controls were just science fiction. At IMTS 98 they will fill nearly every last corner of the recently expended McCormick Place.

AGMA introduced ANSI/AGMA 2015–2–A06—
Accuracy Classification System: Radial System for Cylindrical Gears, in 2006 as the first major rewrite of the
double-flank accuracy standard in over 18 years. This document explains concerns related to the use of
ANSI/AGMA 2015–2–A06 as an accuracy classification system and recommends a revised system that can be of more service to the gearing industry.

The American Society of Mechanical Engineers (ASME) announced at Gear Expo '95 that a national service for the calibration of involute artifacts is now available at the Department of Energy's Y-12 Plant in Oak Ridge, TN.

Powder metallurgy (P/M) techniques have proven successful in displacing many components within the automobile drive train, such as: connecting rods, carriers, main bearing caps, etc. The reason for P/M’s success is its ability to offer the design engineer the required mechanical properties with
reduced component cost.

IMTS exists primarily as a buy-and-sell
North American venue for practically every conceivable technology used in manufacturing, and in that regard it has no equal. There you’ll find on display the latest and greatest technology, from hardware to software and everything in between. But anyone who has attended past shows is aware that IMTS is much more than that. Following is a rundown of "extracurricular" activities you’ll find waiting for your edification
and enjoyment.

IMTS: It can be the best of times or the worst of times. The best because nowhere will you find more equipment, products and services for your business than at McCormick Place, Chicago, in September; the worst because finding your way around the show and around the city can be a hassle.

If you make hardened gears and have not seen any micropitting, then you haven’t looked closely enough. Micropitting is one of the modes of failure that has more recently become of concern to gear designers and manufacturers. Micropitting in itself is not necessarily a problem, but it can lead to noise and sometimes other more serious forms of failure. Predicting when this will occur is the challenge
facing designers.

The AGMA Fall Technical Meeting
provides an opportunity to share ideas
with others on the design, analysis,
manufacturing and application of gears,
gear drives, and related products, as well
as associated processes and procedures.

Earlier this year, a relative of mine, Sidney Mandell, tragically passed away. I had the good fortune to serve with Sidney on the Board of Directors and the Executive Committee of the Machinery Dealers National Association (MDNA). Though he started before me, his MDNA career and mine overlapped for about 2 years. As I think back on the many things I learned form him, one of his favorite phrases keeps come to mind: "We walk in the footsteps of those who have gone before us."

This paper will provide examples of stress levels from conventional root design using a hob and stress levels using an optimized root design that is now possible with PM manufacturing. The paper will also investigate how PM can reduce stresses in the root from transient loads generated by abusive driving.

The great thing about a trade show the size of IMTS is the amount of options available to attendees. If you’re into cars, fighter jets, machine tools,
fighting robots, manufacturing relics or
simply the latest technology advancements in a particular industry, you’ll find it at IMTS 2010.

Following is a report from The Manufacturers Alliance for Productivity and Innovation (MAPI). Founded in 1933, the alliance contributes to the competitiveness of U.S. manufacturing by providing economic research, professional development, and an independent, expert source of manufacturing information.

Indiana Technology and Manufacturing
Companies (ITAMCO) has released iBlue—the first handheld bluetooth transmitter that gathers crucial production data and sends it to bluetooth-enabled smartphones, tablets and computers.

It’s that even-numbered-year time-of-the-year again. The International Manufacturing Technology Show, IMTS 2008, is right around the corner. This 27th installment of the biennial trade show is focusing on connecting global technology.

The heat treatment processing of powder metal (PM) materials like Astaloy requires four steps -- de-waxing, HT sintering, carburizing and surface hardening -- which are usually achieved in dedicated, atmospheric furnaces for sintering and heat treat, respectively, leading to intermediate handling operations and repeated heating and cooling cycles. This paper presents the concept of the multi-purpose batch vacuum furnace, one that is able to realize all of these steps in one unique cycle. The multiple benefits brought by this technology are summarized here, the main goal being to use this technology to manufacture high-load transmission gears in PM materials.

Whether you spent time at Gear Expo in Indianapolis or EMO in Hannover, there was certainly new technology
attracting attention. Machine tools are faster, more efficient and can integrate numerous functions in a single setup. Grinding technology is turning science upside down and inside out with high-speed removal rates and increased throughput.

At Andrew Tool, CMMs have been an integral part of their manufacturing processes for years, but they had never faced a project with such intricate measurements, tight tolerances, heat treatments and a very short time frame requirement.

"Design for manufacturability" (DFM) is a well-established practice, essential to realizing the successful transformation of concepts into mass-produced gears and motion control
devices. And yet, all too often issues that could have been avoided are
identified very late in the process that
impact production costs and schedules.
This suggests that key DFM principles
are often underutilized in practice and
are not applied consistently - or to the
degree necessary - to avoid these negative results.

In 1961 I presented a paper, "Calculating Conjugate Helical Forms," at the semi-annual meeting of the American Gear Manufacturers Association (AGMA). Since that time, thousands of hobs, shaper cutters and other meshing parts have been designed on the basis of the equations presented in that paper. This article presents the math of that paper without the formality of its development and goes on to discuss its practical application.

The trend toward moving coordinate measuring machines to the shop floor to become an integral part of the manufacturing operations brings real time process control within the reach of many companies. Putting measuring machines on the shop floor, however, subjects them to harsh environmental conditions. Like any measuring system, CMMs are sensitive to any ambient condition that deviates from the "perfect" conditions of the metrology lab.

When parts you manufacture pass through numerous processes such as deep hole drilling, machining, hobbing and grinding, a CMM is essential when your customers require 100 percent in-process and final inspection.

In this article, the authors calculated the numerical coordinates on the tooth surfaces of spiral bevel gears and then modeled the tooth profiles using a 3-D CAD system. They then manufactured the
large-sized spiral bevel gears based on a CAM process using multi-axis control and multi-tasking machine tooling. The
real tooth surfaces were measured using a coordinate measuring machine and the tooth flank form errors were detected
using the measured coordinates. Moreover, the gears were meshed with each other and the tooth contact patterns were investigated. As a result, the validity of this manufacturing method was confirmed.

IMTS is about beginnings. This year's show takes place September 8-13 at McCormick Place in Chicago. With more than 1,900 exhibitors expected to occupy more than 1.2 million square feet of exhibit space, there will be plenty of technology on display.

IMTS 94, the Association for Manufacturing Technology's biennial machine tool extravaganza opens September 7 at McCormick Place in Chicago. As always, the size of this show is astonishing. Over 100,000 visitors, enough to populate a medium-size town, will converge on Chicago's lakefront to visit more than 1,200 exhibits spread over the entire McCormick Place complex.

For eight days every other year, the sponsor of the International Manufacturing Technology Show (IMTS), the Association for Manufacturing Technology (AMT), strives to turn Chicago's McCormick Place into a "productivity marketplace," the largest and most completer display and demonstration of manufacturing technology ever seen in the Americas. If the growth of the show is any indicator, that effort has been very successful indeed. With over 1.4 million square feet of exhibit space taking up all five levels and all three exhibit halls of McCormick Place, each level would rank as one of the nation's 200 largest trade shows. That wasn't always the size or scope of the show. Its inception, while impressive for the time, was humble by today's standards.

The authors of last issue's article comparing AGMA, ISO and BS methods for Pitting Resistance Ratings are commended. Trying to compare various methods of rating gears is like hitting a moving target in a thick forest. The use of different symbols, presentations, terminology, and definitions in these standards makes it very difficult. But the greatest problem lies with the authors' use of older versions of these documents. ISO drafts and AGMA standards have evolved at the same time their work was accomplished and edited.

Robots, computers and other signs of high technology abounded at IMTS 94, supporting the claim by many that this was one of the best shows ever. Many of the machines on display had so many robotic attachments and computer gizmos that they looked more like they belonged in some science fiction movie than on the floor of a machine shop.

The purpose of this article is to discuss ISO 4156/ANSI B92.2M-1980 and to compare it with other, older standards still in use. In our experience designing and manufacturing spline gauges and other spline measuring or holding devices for splined component manufacturers throughout the world, we are constantly surprised that so many standards have been produced covering what is quite a small subject. Many of the standards are international standards; others are company standards, which are usually based on international standards. Almost all have similarities; that is, they all deal with splines that have involute flanks of 30 degrees, 37.5 degrees or 45 degrees pressure angle and are for the most part flank-fitting or occasionally major-diameter-fitting.

The first edition of the international calculation method for micropitting—ISO TR 15144–1:2010—was just published
last December. It is the first and only official, international calculation method established for dealing with
micropitting. Years ago, AGMA published a method for the calculation of oil film thickness containing some comments
about micropitting, and the German FVA published a calculation method based on intensive research results. The FVA and the AGMA methods are close to the ISO TR, but the calculation of micropitting safety factors is new.

8 Gear Technology advertisers will have booths at IMTS 92, the largest trade show in the Western Hemisphere. The show opens in Chicago on Sept. 9 and runs through the 17th. More than 800 companies from around the world will cover some 931,000 sq. ft. of exhibit space to show the latest manufacturing technology - everything from forming and fabrication products to environmental and plant safety equipment.

Arrow Gear Company of Downers Grove, IL, has implemented a computer system that fully integrates exchange between all of its computer applications. The ELIMS (Electronic Linkage of Information Management Systems) project has increased manufacturing productivity and reduced lead times.

Custom Gear and Machine, Inc., of Roscoe, IL, recently purchased a Reishauer RZ400 gear grinder and, on one job, has seen the cycle time drop from 40 minutes to six minutes, according to Tim Rose, vice president
of manufacturing, who runs the business with co-owners Dave Patterson and Mike Rasmann.

The geometry factor, which is a fundamental part of the AGMA strength rating of gears, is currently computed using the Lewis parabola which allows computation of the Lewis form factor.(1) The geometry factor is obtained from this Lewis factor and load sharing ratio. This method, which originally required graphical construction methods and more recently has been computerized, works reasonably well for external gears with thick rims.(2-6) However, when thin rims are encountered or when evaluating the strength of internal gears, the AGMA method cannot be used.

"One of the reasons AGMA has been
successful over our 93-year history is
that the association’s agenda, programs
and activities reflect the voices of our members," says Joe T. Franklin, Jr., AGMA President.

A trial test of the calibration procedures outlined in ISO 18653—Gears: Evaluation of Instruments for the Measurement of Individual Gears, shows that the results are reasonable, but a minor change to the uncertainty formula is recommended. Gear measuring machine calibration methods are reviewed. The benefits of using workpiece-like artifacts are discussed, and a procedure for implementing the standard in the workplace is presented. Problems with applying the standard to large gear measuring machines are considered and some recommendations offered.

If the free iPad giveaway from FANUC doesn’t draw you in, the wall-to-wall new machine tool technology displays should have you stopped dead in your tracks. To be exact, there will be 1.2 million square feet of exhibit space that may have your jaw dropping. IMTS may be the last show you want to forget to bring walking shoes to.

An investigation of transmission errors and bearing contact of spur, helical, and spiral bevel gears was performed. Modified tooth surfaces for these gears have been proposed in order to absorb linear transmission errors caused by gear misalignment and to localize the bearing contact. Numerical examples for spur, helical, and spiral bevel gears are presented to illustrate the behavior of the modified gear surfaces with respect to misalignment and errors of assembly. The numerical results indicate that the modified surfaces will perform with a low level of transmission error in non-ideal operating environments.

The following excerpt is from the Revised Manual of Gear Design, Section III, covering helical and spiral gears. This section on helical gear mathematics shows the detailed solutions to many general helical gearing problems. In each case, a definite example has been worked out to illustrate the solution. All equations are arranged in their most effective form for use on a computer or calculating machine.

The concept of "transmission error" is relatively new and stems from research work in the late 1950s by Gregory, Harris and Munro,(1) together with the need to check the accuracy of gear cutting machines. The corresponding commercial "single flank" testing equipment became available in the 1960s, but it was not until about ten years ago that it became generally used, and only recently has it been possible to test reliably at full load and full speed.

The use of dimensionless factors to describe gear tooth geometry seems to have a strong appeal to gear engineers. The stress factors I and J, for instance, are well established in AGMA literature. The use of the rack shift coefficient "x" to describe nonstandard gear proportions is common in Europe, but is not as commonly used in the United States. When it is encountered in the European literature or in the operating manuals for imported machine tools, it can be a source of confusion to the American engineer.

Most gear cutting shops have shelves full of expensive tooling used in the past for cutting gears which are no longer in production. It is anticipated that these cutters will be used again in the future. While this may take place if the cutters are "standard," and the gears to be cut are "standard," most of the design work done today involves high pressure angle gears for strength, or designs for high contact ratio to reduce noise. The re-use of a cutter under these conditions requires a tedious mathematical analysis, which is no problem if a computer with the right software is available. This article describes a computerized graphical display which provides a quick analysis of the potential for the re-use of shaving cutters stored in a computer file.

Micropitting has become a major concern in certain classes of industrial gear applications, especially wind power and other relatively highly loaded, somewhat slow-speed applications, where carburized gears are used to facilitate maximum load capacity in a compact package. While by itself the appearance of micropitting does not generally cause
much perturbation in the overall operation of a gear system, the ultimate
consequences of a micropitting failure
can, and frequently are, much more
catastrophic.

In the hypercompetitive race to increase automobile efficiency,
Metaldyne has been developing its balance shaft module line with Victrex
PEEK polymer in place of metal gears.
The collaborative product development
resulted in significant reductions in
inertia, weight and power consumption,
as well as improvement in noise, vibration and harshness (NVH) performance.

A study of AGMA 218, the draft ISO standard 6336, and BS 436: 1986 methods for rating gear tooth strength and surface durability for metallic spur and helical gears is presented. A comparison of the standards mainly focuses on fundamental formulae and influence factors, such as the load distribution factor, geometry factor, and others. No attempt is made to qualify or judge the standards other than to comment on the facilities or lack of them in each standard reviewed. In Part I a comparison of pitting resistance ratings is made, and in the subsequent issue, Part II will deal with bending stress ratings and comparisons of designs.

Bankruptcy filings have not noticeably declined despite the economic recovery of the Reagan years. Businesses continue to receive notices that their customers have filed bankruptcy. Many of them are writing off significant losses each year as a result. despite the frequent use of bankruptcy by debtors, many business owners and managers have little or no idea of the pot-bankruptcy remedies available to them.

Metrology is a vital component of gear manufacturing. Recent changes in this area, due in large part to the advent of computers, are highlighted in this article by comparison with more traditional methods.

A few months ago at the AGMA management seminar, I was surprised by the feverish note taking that went on at a presentation on marketing. The sight reminded me that while many of us in the gear industry are good engineers, designers, and mangers, we are often not as familiar - or comfortable - with less concrete concepts, such as marketing.

Gear tooth wear and micropitting are very difficult phenomena to predict
analytically. The failure mode of micropitting is closely correlated to the lambda ratio. Micropitting can be the limiting design parameter
for long-term durability. Also, the failure mode of micropitting can progress to wear or macropitting, and then go on to manifest more severe failure modes, such as bending. The results of a gearbox test and manufacturing process development program will be presented to evaluate super-finishing and its impact on micropitting.

Five years of effort by AGMA came to fruition in January with the publishing of a report from the Department of Commerce. This "National Security Assessment of the U.S. Gear Industry" indicates that if serious measures are not taken, the gear industry's future is in jeopardy. It also sets the tone for confronting major challenges now looming large in our industry.

Except for higher-end gear applications
found in automotive and aerospace transmissions, for example,
high-performance, sintered-steel
gears match wrought-steel gears in strength and geometrical quality. The enhanced P/M performance is due largely to advances in powder metallurgy over last two decades, such as selective surface densification, new materials and
lubricants for high density and
warm-die pressing. This paper is a
review of the results of a decade of
research and development of high- performance, sintered-steel gear prototypes.

Capstan Atlantic, located in Wrentham, Massachusetts, produces powder metal gears, sprockets and complex structural
components. The company has provided unique powder metal products in a variety of industries including automotive, business machines, appliances, lawn and garden equipment
and recreational vehicles.

QuesTek Innovations LLC is applying its Materials by Design computational design technology to develop a new
class of high-strength, secondary hardening gear steels that are optimized for high-temperature, low-pressure (i.e., vacuum) carburization. The new alloys offer three different levels of case hardness (with the ability to “dial-in” hardness profiles, including exceptionally high case hardness), and their high core strength, toughness and other properties offer the potential to reduce drivetrain weight or increase power density relative to incumbent alloys such as AISI 9310 or Pyrowear Alloy 53.

Modern gearboxes are characterized by high torque load demands, low running noise and compact design. In order
to fulfill these demands, profile and lead modifications are being applied more often than in the past. This paper will focus on how to produce profile and lead modifications by using the two most common grinding processes—threaded
wheel and profile grinding. In addition, more difficult modifications—such as defined flank twist or topological flank corrections—will also be described in this paper.

One of the best ways to learn the ISO 6336 gear rating system is to recalculate the capacity of a few existing designs and to compare the ISO 6336 calculated capacity to your experience with those designs and to other rating methods. For these articles, I'll assume that you have a copy of ISO 6336, you have chosen a design for which you have manufacturing drawings and an existing gear capacity calculation according to AGMA 2001 or another method. I'll also assume that you have converted dimensions, loads, etc. into the SI system of measurement.

We talked with a number of major
companies in the midst of their planning
and strategizing for IMTS 2012,
with the thought of determining just
how much things have in fact changed
for exhibitors regarding the trade show
experience.

In our never-ending quest to bring our readers information about he unusual, the unique and-dare we say it?-the bizarre, the Addendum Staff has traveled for this issue to the wilds of Darkest Tennessee and the Museum of Appalachia. This museum of Appalachian fold art, crafts and history is located in Norris, TN, about 16 miles north of Knoxville. Among the 250,000 items collected by the museum's founder, John Rice Irwin, is a "thing," a "contraption," an "objet trouve"; to wit, Asa Jackson's mysterious machine.

Nashville - One of the highlights of this year's SME Advanced Gear Processing and Manufacturing Clinic was a tour of the new GM Saturn automobile manufacturing plant outside the city. There in the Tennessee hills is a hopeful vision of the future of the American automobile industry. It may well be the future of American large-scale manufacturing in general.

On many occasions a reasonably approximate, but not exact, representation of an involute tooth profile is required. Applications include making drawings, especially at enlarged scale, and laser or EDM cutting of gears, molds, and dies used to produce gears. When numerical control (NC) techniques are to be used, a simple way to model an involute can make the NC programming task much easier.

simplified equations for backlash and roll test center distance are derived. Unknown errors in measured tooth thickness are investigate. Master gear design is outlined, and an alternative to the master gear method is described. Defects in the test radius method are enumerated. Procedures for calculating backlash and for preventing significant errors in measurement are presented.

Just back from IMTS and once again, I'm struck by the enormous vitality and strength of the manufacturing sector of the U.S. economy. It has made a phoenix-like rise from the grave dug for it by pundits in the '80s and has come back more robust and competitive than ever.

Powder metallurgy (P/M) is a precision metal forming technology for the manufacture of parts to net or near-net shape, and it is particularly well-suited to the production of gears. Spur, bevel and helical gears all may be made by made by powder metallurgy processing.

Grinding in one form or another has been used for more than 50 years to correct distortions in gears caused by the high temperatures and quenching techniques associated with hardening. Grinding improves the lead, involute and spacing characteristics. This makes the gear capable of carrying the high loads and running at the high pitch line velocities required by today's most demanding applications. Gears that must meet or exceed the accuracy requirements specified by AGMA Quality 10-11 or DIN Class 6-7 must be ground or hard finished after hear treatment.

The two reports referred to in this article, "The people wise Organization" and "House Divided: Views on Change from Top Management - and Their Employees," crossed our desks some weeks ago. They stimulated a fair amount of discussion here, and we hope they do the same in your offices. We welcome your responses. How do you view the corporate/competitive environment of the next few years? How do you see yourself and your company fitting in? Can these ideas work in the gear industry? Let us now what you think.

His resume reads like that of many gear engineers of his generation: the stint in the army during World War II; the break for college in the late 40s; deliberately vague descriptions of projects for the Air Force in the New Mexico desert in the early 50s; the corporate engineering jobs later on in the decade.

The last two months have been both a time of difficulty and of growth for Gear Technology. Unexpectedly, I found myself in the hospital having surgery, and consequently out of commission for several weeks. At the same time, two individuals on our staff lost family members, and most of this period saw us getting ready for this preshow IMTS issue while being seriously short-staffed.

You're already a veteran of the computer revolution. Only you and your controller know how much money you've spent and only your spouse knows how many sleepless nights you've had in the last ten years trying to carve out a place in the brave new world of computerized gear manufacturing. PC's, CNCs, CAD, CAM, DNC, SPC, CMM: You've got a whole bowl of alphabet soup out there on the shop floor. Overall these machines have lived up to their promises. Production time is down, quality is up. You have fewer scrapped parts and better, more efficient machine usage.

At a time when there are many pressures on the Gear Industry and its representative Association, the
American Gear Manufacturers Association, it seems particularly appropriate that Gear Technology - The
Journal of Gear Manufacturing appears. AGMA is particularly pleased to have the opportunity to write the first editorial for this magazine.

Surface-hardened, sintered powder metal gears are increasingly used in power transmissions to reduce the cost of gear production. One important problem is how to design with surface durability, given the porous nature of sintered gears. Many articles have been written about mechanical characteristics, such as tensile and bending strength, of sintered materials, and it is well-known that the pores existing on and below their surfaces affect their characteristics (Refs. 1-3). Power transmission gears are frequently employed under conditions of high speed and high load, and tooth surfaces are in contact with each other under a sliding-rolling contact condition. Therefore it is necessary to consider not only their mechanical, but also their tribological characteristics when designing sintered gears for surface durability.

Increasingly gear designers and product engineers are capitalizing on the economic advantages of powder metallurgy (P/M) for new and existing gear applications. Powder metal gears are found in automobiles, outdoor power equipment transmissions and office machinery applications as well as power hand tools, appliances and medial components.

Chicago- Results of recent studies on residual stress in gear hobbing, hobbing without lubricants and heat treating were reported by representatives of INFAC (Instrumented Factory for Gears) at an industry briefing in March of this year.

Gear gashing is a gear machining process, very much like gear milling, utilizing the principle of cutting one or more tooth (or tooth space) at a time. The term "GASHING" today applies to the roughing, or roughing and finishing, of coarse diametral pitch gears and sprockets. Manufacturing
these large coarse gears by conventional methods of rough and finish hobbing can lead to very long machining cycles and uneconomical machine utilization.

In the quest for ever more exacting and compact commercial gears, precision abrasives are playing a key production role - a role that can shorten cycle time, reduce machining costs and meet growing market demand for such requirements as light weights, high loads, high speed and quiet operation. Used in conjunction with high-quality grinding machines, abrasives can deliver a level of accuracy unmatched by other manufacturing techniques, cost-effectively meeting AGMA gear quality levels in the 12 to 15 range. Thanks to advances in grinding and abrasive technology, machining has become one of the most viable means to grind fast, strong and quiet gears.

What is so unique about gear manufacturing and inspection? Machining is mostly associated with making either flat or cylindrical shapes. These shapes can be created by a machine's simple linear or circular movements, but an involute curve is neither a straight line nor a circle. In fact, each point of the involute curve has a different radius and center of curvature. Is it necessary to go beyond simple circular and linear machine movements in order to create an involute curve? One of the unique features of the involute is the fact that it can be generated by linking circular and linear movements. This uniqueness has become fertile soil for many inventions that have simplified gear manufacturing and inspection. As is the case with gear generating machines, the traditional involute inspection machines take advantage of some of the involute properties. Even today, when computers can synchronize axes for creating any curve, taking advantage of involute properties can be very helpful. I t can simplify synchronization of machine movements and reduce the number of variables to monitor.

A change has taken place within the industry that is going to have an enormous effect on the marketing, sales, and purchasing of gear manufacturing and related equipment. This change was the American Gear Manufacturers' Association, first biennial combination technical conference and machine tool minishow.

Gear Technology speaks with David Goodfellow, president of American Pfauter, L.P., and Pfauter-Maag Cutting tools, L.P., to get his impressions about the state of the gear industry and its prospects for the future.

On of the key questions confronting any company considering ISO 9000 certification is, how much is this going to cost? The up-front fees are only the beginning. Dissect the ISO 9000 certification procedure with an eye for hidden costs, and two segments of the process will leap out - the cost of consultants and the cost of making in-house improvements for the sake of passing certification. Most of these costs can be controlled by careful selection f the right consultant in the first place.

Most steel gear applications require appreciable loads to be applied that will result in high bending and compressive stresses. For the material (steel) to meet these performance criteria, the gear must be heat treated. Associated with this thermal processing is distortion. To control the distortion and achieve repeatable dimensional tolerances, the gear will be constrained during the quenching cycle of the heat treatment process. This type of fixture quenching is the function of gear quench pressing equipment.

The following excerpt is from the Revised Manual of Gear Design, Section III, covering helical and spiral gears. This section on helical gear mathematics shows the detailed solutions to many general helical gearing problems. In each case, a definite example has been worked out to illustrate the solution. All equations are arranged in their most effective form for use on a computer or calculating machine.

Minimizing gear losses caused by churning, windage and mesh friction is important if plant operating costs and
environmental impact are to be minimized. This paper concentrates on mesh friction losses and associated scuffing risk. It describes the preliminary results from using a validated, 3-D Finite Element Analysis (FEA) and Tooth Contact Analysis (TCA) program to optimize cylindrical gears for low friction losses without compromising transmission error (TE), noise and power density. Some case studies and generic procedures for minimizing losses are presented. Future
development and further validation work is discussed.

Analysis of helical involute gears by tooth contact analysis shows that such gears are very sensitive to angular misalignment leading to edge contact and the potential for high vibration. A new topology of tooth surfaces of helical gears that enables a favorable bearing contact and a reduced level of vibration is described. Methods for grinding helical gears with the new topology are proposed. A TCA program simulating the meshing and contact of helical gears with the new topology has been developed. Numerical examples that illustrate the proposed ideas are discussed.

Flute Index
Flute index or spacing is defined as the variation from the desired angle between adjacent or nonadjacent tooth faces measured in a plane of rotation. AGMA defines and provides tolerance for adjacent and nonadjacent flute spacing errors. In addition, DIN and ISO standards provide tolerances for individual flute variation (Fig. 1).

Who wants or needs technical details about gearing? Who cares about it? Three out of every four people who are reading this magazine make up at least 75% of those who have an interest in the subject. The members of AGMA, EUROTRANS, JGMA and JSIM have an interest. All the people attending the Gear Expo in Detroit have an interest. Clearly, however, the people with the most pressing interest in our industry are our customers, the end users of gear products. The unfortunate reality, though, is that in many cases, these customers don't even know that's what they want.

Surface roughness measuring of gear teeth can be a very frustrating experience. Measuring results often do not correlate with any functional characteristic, and many users think that they need not bother measuring surface roughness, since the teeth are burnished in operation. They mistakenly believe that the roughness disappears in a short amount of time. This is a myth! The surface indeed is shiny, but it still has considerable roughness. In fact, tests indicate that burnishing only reduces the initial roughness by approximately 25%.

With all the heated debate and hoopla surrounding ISO 9000 certification, everyone seems to have an opinion about whether to sign up. Executives in the gear industry are flooded with information and ideas that often seem at odds. Gear Technology asked AGMA executive director Joe T. Franklin, Jr. to give an industry perspective on the pros and cons of ISO 9000 certification.

A study was performed to evaluate fault detection effectiveness as applied to gear-tooth pitting-fatigue damage. Vibration and oil-debris monitoring (ODM) data were gathered from 24 sets
of spur pinion and face gears run
during a previous endurance evaluation
study.

Publisher Michael Goldstein sat down with Dr. Thomas Koepfer, whose family company, Josef Koepfer & Söhne GmbH, was founded in 1867. Over the years, the Koepfer name has become one of the best-known in the gear industry, with company operations including the manufacture of gear machines, cutting tools and gears.

Tom Lang liked what he saw in the Gear Generation Pavilion at IMTS 2004. Standing in his booth, Kapp Technologies’ vice president/general manager talked with many attendees during the show and afterward said:
“We had an increase of both quality and quantity of visitors.”

Over the past few months we've talked with a lot of gear manufacturers. Many of them tell us business is strong, while others are struggling with reduced demand. The difference between them isn't so much in the quality of their manufacturing operations, but rather trends in the end markets they serve.

Measurement institutions of seven different countries — China, Germany, Japan, Thailand, Ukraine, United Kingdom and the U.S. — participated in the implementation of the first international comparison of involute gear measurement standards. The German metrology institute Physikalisch-Technische Bundesanstalt (PTB) was chosen as the pilot laboratory as well as the organizer. Three typical involute gear measurement standards provided by the PTB were deployed for this comparison: a profile, a helix and a pitch measurement standard. In the final analysis, of the results obtained from all participants, the weighted mean was evaluated as reference value for all 28 measured parameters. However, besides the measurement standards, the measured parameters, and, most importantly, some of the comparison results from all participants are anonymously presented. Furthermore, mishandling of the measurement standards as occurred during the comparison will be illustrated.

A gear design optimization approach applied to reduce tooth contact temperature and noise excitation of a high-speed spur gear pair running without lubricant. Optimum gear design search was done using the Run Many Cases software program. Thirty-one of over 480,000 possible gear designs were considered, based on low contact temperature and low transmission error. The best gear design was selected considering its manufacturability.

I was recently honored by the European Association of Machine Tool Merchants (EAMTM) at the organization's annual meeting this past June in Mallorea, Spain. The organization inducted me as a Fellow, EAMTM's highest honor, bestowed on members who have made significant contributions as volunteers serving the organization, which was originally founded in 1940. I felt especially honored, as I am only the 19th person and the second non-European to have been given this award.

The grinding/abrasives market is rapidly changing, thanks to new technology, more flexibility and an attempt to lower customer costs. Productivity is at an all-time high in this market, and it’s only going to improve with further R&D. By the time IMTS 2014 rolls around this September, the gear market will have lots of new toys and gadgets to offer potential customers. If you haven’t upgraded any grinding/abrasives equipment in the last five years, now might be a good time to consider the investment.

There’s a bustle of activity as exhibitors prepare for America’s most significant manufacturing trade show. The red carpets are ready, the lights are being tested, and the crowds are gathering with anticipation. Amid the excitement, Gear Technology has managed to sneak under the usher’s ropes to provide you with this advance look at some of the gear-related products and technologies that will be featured at IMTS 2004.

LMS International helped a Fiat subsidiary develop a new, dynamic vibro-acoustic prediction method to reduce design time and engineering costs through accurate prediction of gear noise in the design phase.

Traditionally, gear rating procedures consider manufacturing accuracy in the application of the dynamic factor, but
only indirectly through the load distribution are such errors in the calculation of stresses used in the durability and gear strength equations. This paper discusses how accuracy affects the calculation of stresses and then uses both statistical
design of experiments and Monte Carlo simulation techniques to quantify the effects of different manufacturing and
assembly errors on root and contact stresses.

Gear making and heat treating pair
together like a fine cabernet and filet
mignon. Now for the first time, the two
industries are embracing this symbiotic
relationship by co-locating their industry events this fall in Indianapolis. ASM International’s 2009 Heat Treating Society Conference and Exposition and Gear Technology’s favorite trade show, Gear Expo, are teaming up September 14–17 at the Indiana Convention Center in Indianapolis.

Imagine the flexibility of having one
machine capable of milling, turning,
tapping and gear cutting with deburring
included for hard and soft material. No, you’re not in gear fantasy land. The technology to manufacture gears on non gear-dedicated, mult-axis machines has existed for a few years in Europe, but has not yet ventured into mainstream manufacturing. Deckel Maho Pfronten, a member of the Gildemeister Group, took the sales plunge this year, making the technology available on most of its 2009 machines.

It may not be widely recognized that most of the inspection data supplied by inspection equipment, following the
practices of AGMA Standard 2015 and similar standards, are not of elemental accuracy deviations but of some form of composite deviations. This paper demonstrates the validity of this “composite” label by first defining the nature of a true
elemental deviation and then, by referring to earlier literature, demonstrating how the common inspection practices for involute, lead (on helical gears), pitch, and, in some cases, total accumulated pitch, constitute composite measurements.

Two high-volume gear production cells grace the shop floor at Delta Research Corporation in Livonia, Michigan. Thanks to lean manufacturing, these cells have never shipped a defective part to a customer since they were developed over three years ago.

Look beyond the obvious, and you may
well find a better way to machine a part,
and serve your customer better. That’s
the lesson illustrated in a gear machining
application at Allied Specialty
Precision Inc. (ASPI), located in Mishawaka, Indiana.

Most readers are at least familiar with continuous improvement programs such as lean and six sigma. Perhaps your shop or company is well along in the implementation of one or the other—if not both. But what about theory of constraints (TOC), introduced in Dr. Eliyahu Goldratt’s 1984 book, The Goal? Despite its rather negative-sounding name, this continuous improvement process has much to offer
manufacturers of all stripes. And when combined with lean and six sigma, the results can be dramatic. Dr. Lisa Lang, a TOC consultant and speaker, explains why and how in the following Q&A session with Gear Technology.

This paper presents the results of research directed at measuring the total stress in a pair of statically loaded and carburized spur gears. Measurements were made to examine the change in total stress as a function of externally applied load and depth below the surface.

Founded in 1927 as the Machine Tool Show and held every two years, the International Manufacturing Technology Show (IMTS) has grown into the largest manufacturing trade show in both North and South America. The statistics for the 1998 show offer a glimpse of the magnitude. Over 1,440 exhibitors showed off 60 million pounds of machinery and went through 5 million pounds of display materials during the week long show. The show organizers themselves sent out 2,632,560 promotional pieces. Twenty-three foreign machine tool associations participated. It took 4,600 trucks to get everything to McCormick Place for the show. There were 450 journalists covering the event, which was attended by 121,764 people. There was $1,034.618,000 worth of business transacted on the show floor of IMTS 1998.

This article examines the dry hobbing capabilities of two cutting tool materials—powder metallurgical high-speed steel (PM-HSS) and cemented carbide. Cutting trials were carried out to analyze applicable cutting parameters and possible tool lives as well as the process reliability. To consider the influences of the machinability of different workpiece materials, a case hardening steel and
a tempered steel were examined.

They only let the Addendum team on the show floor for one day (they said it was something to do with their liability insurance...), but here's what our intrepid team of gear fanatics noticed at IMTS 2012.

It wasn’t so very long ago that a high school-educated, able-bodied person with a will to work typically had little trouble finding a decent job in manufacturing. Whether at an area job
shop, an OEM plant or auto plant—work was to be had. Work that paid well
enough to marry, buy a home, feed, raise
and educate a family—with even enough
left over for a modest retirement pension.

The face load factor is one of the most important items for a gear strength calculation. Current standards propose formulae for face load factor, but they are not always appropriate. AGMA 927 proposes a simpler and quicker algorithm that doesn't require a contact analysis calculation. This paper explains how this algorithm can be applied for gear rating procedures.

In March 1989, the U.S. Trade Representative requested the U.S. International Trade Commission to conduct an investigation and prepare a report on the competitive position of the U.S. gear industry in U.S. and global markets.

If anyone should ever need convincing
that the state of American manufacturing is in ongoing decline, consider this: the state of Michigan has the highest concentration of engineers in the country, yet also has the highest unemployment rate. But there are ripples of hope out there as grassroots and otherwise organized groups are fighting the good fight in an attempt to reverse that trend.

Results from the Technical University
of Munich were presented in a previous technical article (see Ref. 4). This
paper presents the results of Ruhr University Bochum. Both research groups
concluded that superfinishing is one of the most powerful technologies for
significantly increasing the load-carrying capacity of gear flanks.

Another year, another AGMA Fall Technical Conference. But this is no ho-hum event. Not when every year, the conference attracts some of the greatest mechanical engineering minds on the planet, along with representatives of the world’s greatest manufacturing entities. And who knows—perhaps one day there will be an extraterrestrial contingent—the science is that good. And all of it readily applicable to real-world manufacturing.

The focus of the following presentation is two-fold: 1) on tests of new geometric variants; and 2) on to-date, non-investigated operating (environmental) conditions. By variation of non-investigated eometric parameters and operation conditions the understanding of micropitting formation is improved. Thereby it is essential to ensure existent calculation methods and match them to results of the comparison between large gearbox tests and standard gearbox test runs to allow a safe forecast of wear due to micropitting in the future.

The hobbing and generation grinding production processes are complex due to tool geometry and kinematics. Expert knowledge and extensive testing are required for a clear attribution of cause to work piece deviations. A newly developed software tool now makes it possible to simulate the cutting procedure of the tool and superimpose systematic deviations on it. The performance of the simulation
software is illustrated here with practical examples. The new simulation tool allows the user to accurately predict the effect of errors. With this knowledge, the user can design and operate optimal, robust gearing processes.

There's a reason they call it catastrophic gear failure: For example, if the line goes down at a large aluminum rolling mill because a gear set goes bad, the cost can run up to a whopping $200,000 a week. Even in smaller operations, the numbers alone (not to mention all the other problems) can be a plant manager's worst nightmare.

Another year has passed and, because of the short term ups and downs of the economy, it's still hard to judge whether we are in an appreciably different place than we were a year ago. The economy doesn't seem to be worse than it was, but it also doesn't seem to be a whole lot better.

We make a lot of single-start worm and worm gear sets, and it always seems as though we're buying another special hob. We also do a lot of spur gear cutting, and the spur gear hobs and the worm gear hobs look alike, so we wonder why we cannot use the standard hobs for cutting worm gears too. Can we do this?

Business ethics are like apple pie and motherhood. Few people are willing to come out agin'em. But in reablity, apple pie is full of fat and refined sugar, motherhood is not what it was when June Cleaver ran the kitchen, and business ethics? Well, it's always been easier to talk about them than to actually practice them, and things certainly haven't improved in the last few years.

"Values" is one of he buzzwords we hear everywhere today. Family values. Traditional values. Alternative values. Along with a balanced budget, less government and more fiber in our diets, "values" - and their practical counterparts, "ethics" - are being promoted as one of the simple, obvious solutions to what ails us as a country and as individuals.

When designing hardened and ground spur gears to operate with minimum noise, what are the parameters to be considered? should tip and/or root relief be applied to both wheel and pinion or only to one member? When pinions are enlarged and he wheel reduced, should tip relief be applied? What are the effects on strength, wear and noise? For given ratios with enlarged pinions and reduced wheels, how can the gear set sized be checked or adjusted to ensure that the best combination has been achieved?

Can a gear profile generated by the hobbing method be an ideal involute? In strictly theoretical terms - no, but in practicality - yes. A gear profile generated by the hobbing method is an approximation of the involute curve. Let's review a classic example of an approximation.

I noted with interest the beginning of Gear Technology's three-part series on ISO 9000 certification. I also recently attended Brown & Sharpe's/Leitz gear metrology seminar. Both events caused me to smile and reflect.

What follows is the first of a series of interviews Gear Technology is conducting with leaders in the gear industry. We will be asking them for their insights on where the industry is, where it's been and where they see it going in the future. Our first interview is with Jim Gleason, president and chairman of Gleason Corporation, Rochester, NY.

Might some of you may be tempted to skip IMTS this year? Business is just so-so. You can’t afford to be away from the shop. It will be a waste of time because you don’t have the budget for new machine tools or new technology anyway. You’ve cut back on travel expenses. It’s your wife’s birthday...

Most companies spend this time of year crystal ball gazing. Managers want to know the future so they can make projections, plan schedules, determine budgets and make major decisions that will ensure their success.

It used to be that a shop with hustle and plenty of big, fast machines could thrive using a manual system. But no more. Today's economic environment requires more and more in the way of topnotch service and quick turnaround - which frequently means a completely integrated shop floor control system.

These days it's hard to get through breakfast without reading or hearing another story about how the computer is changing the way we live, sleep, eat, breathe, make things and do business. The message is that everything is computerized now, or, if it isn't, it will be by next Tuesday at the latest, Well, maybe.

This section will deal with the use of gear inspection for diagnostic purposes rather than quality determination. The proper evaluation of various characteristics in the data can be useful for the solution of quality problems. It is important to sort out whether the problem is coming from the machine, tooling and/or cutters, blanks, etc. An article by Robert Moderow in the May/June 1985 issue of Gear Technology is very useful for this purpose.

Much about ISO 9000 is the subject of noisy debate. But on one thing almost everyone, true believers and critics alike, agrees: Getting ISO 9000 certification can be expensive. Companies can expect to spend at least $35,000 for basic certification and six-month checkup fees over a three-year period. These figures do not include hidden costs like time and money spent on internal improvements required to meet ISO 9000 certification. But the really big-ticket items in the process are employee time and the cost of bringing in outside consultants. Many ISO 9000 consultants charge upwards of $1,800 a day.

If someone were to tell you that he had a gear material that was stronger per pound than aluminum, as wear-resistant as steel, easier to machine than free-machining steel and capable of producing gears domestically for 20% less than those now cut from foreign made forgings, would you consider that material to be "high tech"? Probably. Well, throw out all the pre-conceived notions that you may have had about "high tech" materials. The high-performance material they didn't teach you about in school is austempered ductile iron (ADI).

This paper presents an original method for computing the loaded mechanical behavior of fiber reinforced polymer gears. Although thermoplastic gears are unsuitable for application transmitting
high torque, adding fibers can significantly increase their performance. The particular case of
polyamide 6 + 30% glass fibers is studied in this paper.

Ausforming, the plastic deformation of heat treatment steels in their metastable, austentic condition, was shown several decades ago to lead to quenched and tempered steels that were harder, tougher and more durable under fatigue-type loading than conventionally heat-treated steels. To circumvent the large forces required to ausform entire components such as gears, cams and bearings, the ausforming process imparts added mechanical strength and durability only to those contact surfaces that are critically loaded. The ausrolling process, as utilized for finishing the loaded surfaces of machine elements, imparts high quality surface texture and geometry control. The near-net-shape geometry and surface topography of the machine elements must be controlled to be compatible with the network dimensional finish and the rolling die design requirements (Ref. 1).

In some gear dynamic models, the effect of tooth flexibility is ignored when the model determines which pairs of teeth are in contact. Deflection of loaded teeth is not introduced until the equations of motion are solved. This means the zone of tooth contact and average tooth meshing stiffness are underestimated, and the individual tooth load is overstated, especially for heavily loaded gears.
This article compares the static transmission error and dynamic load of heavily loaded, low-contact-ratio spur gears when the effect of tooth flexibility has been considered and when it has been ignored. Neglecting the effect yields an underestimate of resonance speeds and an overestimate of the dynamic load.

This presentation introduces a new procedure that - derived from exact calculations - aids in determining the parameters of the validation testing of spiral bevel and hypoid gears in single-reduction axles.

For heat treatment of tool and alloy steels, the end-user has a wide range of basic types of heat treating equipment to choose from. This article reviews them and details the criteria that must be considered in selecting equipment for a specific application. In making this choice, the most important criterion must be the quality of the tool or part after processing.

The efficiency of a gearbox is the output energy divided by the input energy. It depends on a variety of factors. If the complete gearbox assembly in its operating environment is observed, then the following efficiency influencing factors
have to be considered

The availability of technical software has grown rapidly in the last few years because of the proliferation of personal computers. It is rare to find an organization doing technical work that does not have some type of computer. For gear designers and manufacturers, proper use of the computer can mean the difference between meeting the competition or falling behind in today's business world. The right answers the first time are essential if cost-effective design and fabrication are to be realized. The computer is capable of optimizing a design by methods that are too laborious to undertake using hard calculations. As speeds continue to climb and more power per pound is required from gear systems, it no longer is possible to design "on the safe side" by using larger service factors. At high rotational speeds a larger gear set may well have less capacity because of dynamic effects. The gear engineer of today must consider the entire gear box or even the entire rotating system as his or her domain.

Temperature Induced Dimensional Changes
Temperature causes various materials to change size at different rate, known as their Coefficients of Expansion (COE). The effects of this phenomenon on precision dimensional measurements are continuous and costly to industry. Precautions can be taken to allow parts and gages to temperature stabilize before conducting gage R & R studies, but the fact remains that on the shop floor temperatures vary all the time. The slow pace at which industry has accepted this reality probably has to do with the subtlety of these tiny size variations and our inability to sense gradual, but significant temperature changes.

Of timing is crucial in the successful implementation of good ideas, then now is the time to reinstate a good idea that fell into disfavor in the mid-1980s. Now is the time to include the investment tax credit as part of whatever inevitable tax structure tinkering is going to take place during this election year.

Precision gears play a vital role in today's economy. Through their application, automobile transmissions are more compact and efficient, ships sail faster, and diesel locomotives haul more freight. Today great emphasis is being placed upon the reduction of noise in all gear applications and, to be quiet, gears must be accurate.

One of the major problems of plastic gear design is the knowledge of their running temperature. Of special interest is the bulk temperature of the tooth to predict the fatigue life, and the peak temperature on the surface of the tooth to avert surface failure. This paper presents the results of an experimental method that uses an infrared radiometer to measure the temperature variation along the profile of a plastic gear tooth in operation.
Measurements are made on 5.08, 3.17, 2.54, 2.12 mm module hob cut gears made from nylon 6-6, acetal and UHMWPE (Ultra High Molecular Weight Polyethylene). All the tests are made on a four square testing rig with thermoplastic/steel gear pairs where the
plastic gear is the driver. Maximum temperature prediction curves obtained through statistical analysis of the results are presented and compared to data available from literature.

Popular wisdom has it that manufacturing in the United States is no longer a viable entity. We are told that quality is poor, skilled labor is difficult to obtain, if not impossible, demand is low, and the government is helping to discourage business. So what should we do, give up?

AGMA Voices is a new feature brought to you by Gear Technology in cooperation with the American Gear Manufacturers
Association. AGMA Voices will give you opinions, insight and information presented by various AGMA staff members, board members, committee heads and volunteers. In this column, Gear Technology will bring you guest editorials from the gear industry’s leading association.

The recently available capability for the free-form milling of gears of various gear types and sizes — all within one manufacturing system — is becoming increasingly recognized as a flexible machining process for gears.

The purpose of gear inspection is to:
Assure required accuracy and quality,
Lower overall cost of manufacture by controlling rejects and scrap,
Control machines and machining practices and maintain produced accuracy as machines and tools wear,
Determine hear treat distortions to make necessary corrections.

The design of any gearing system is a difficult, multifaceted process. When the system includes bevel gearing, the process is further complicated by the complex nature of the bevel gears themselves. In most cases, the design is based on an evaluation of the ratio required for the gear set, the overall envelope geometry, and the calculation of bending and contact stresses for the gear set to determine its load capacity. There are, however, a great many other parameters which must be addressed if the resultant gear system is to be truly optimum.
A considerable body of data related to the optimal design of bevel gears has been developed by the aerospace gear design community in general and by the helicopter community in particular. This article provides a summary of just a few design guidelines based on these data in an effort to provide some guidance in the design of bevel gearing so that maximum capacity may be obtained. The following factors, which may not normally be considered in the usual design practice, are presented and discussed in outline form:
Integrated gear/shaft/bearing systems
Effects of rim thickness on gear tooth stresses
Resonant response

The implementation of powder metal (PM)components in automotive applications increases continuously, in particular for more highly loaded gear components like synchromesh mechanisms. Porosity and frequently inadequate material properties of PM materials currently rule out PM for automobile gears that are subject to high loads. By increasing the density of the sintered gears, the mechanical properties are improved. New and optimized materials designed to allow the production of high-density PM gears by single sintering may change the situation in the future.

Powder metal. To gear makers today, the phrase conjures images of low power applications in non-critical systems. As powder metal technology advances, as the materials increase in density and strength, such opinions are changing. It is an ongoing, evolutionary process and one that will continue for some time. According to Donald G. White, the executive director of the Metal Powder Industries Federation, in his State-of-the-P/M Industry - 1999 report. "The P/M world is changing rapidly and P/M needs to be recognized as a world-class process - national, continental and even human barriers and prejudices must be eliminated - we must join forces as a world process - unified in approach and goals."

Today, as part of filling a typical gear hobbing or shaping machine order, engineers are required to perform an SPC acceptance test. This SPC test, while it is contractually necessary for machine acceptance, is not a machine acceptance test. It is a process capability test. It is an acceptance of the machine, cutting tool, workholding fixture, and workpiece as integrated on the cutting machine, using a gear measuring machine, with its work arbor and evaluation software, to measure the acceptance elements of the workpiece.

Dear Editor:
Re: Your editorial and "Viewpoint" by Joe Arvin.
Both you and Mr. Arvin make some valid points. Your editorial appears to be a response to Mr. Arvin's "Viewpoint." This is a response to both

Dictatorships can be stifling. In an autocratic organization, employees seldom participate in decisions that affect them. By establishing a collaborative environment, you allow everyone to play a role in making your organization a success.

Whether gear engineers have to replace an old gear which is worn out, find out what a gear's geometry is after heat treatment distortion, or just find out parameters of gears made by a competitor, sometimes they are challenged with a need to determine the geometry of unknown gears. Depending on the degree of accuracy required, a variety of techniques are available for determining the accuracy of an unknown gear. If a high degree of precision is important, a gear inspection device has to be used to verify the results. Frequently, several trial-and-error attempts are made before the results reach the degree of precision required.

Gears are extremely complex shapes. Coordinate measuring machines, or CMMs, are designed to measure complex shapes. It seems to follow that CMMs world, therefore, be the ideal tool for measuring gears. But the answer is not so simple.

Next year will be the 500th anniversary of Christopher Columbus' famous "discovery" of America. Poor Columbus has fallen on hard times of late, what with revisionist historians smacking their lips over his more notable failures and reminding us that American natives have a vastly different point of view on this Great American Success Story. But before we relegate the Great Navigator to the scrap heap of trashed-over heros, let's take one last look at some of the positive lessons to be learned from the Columbus experience - ones that could be instructive to our current situation in the American gear industry.

Question: When evaluating charts from a gear inspection machine, it is sometimes found that the full length of the profile traces vary, and that sometimes they are less than the length of active profile (above start of active profile-SAP) by up to 20%. This condition could be caused by a concentricity error between tooth grinding and shaping, or by unequal stock removal when grinding. (See Fig. 1.) Is it possible that some of the variation is coming from the inspection machine? How can variation from the inspection machine be reduced?

The whole point of a trade show is to get leads that will turn into sales. No matter how attractive your booth was, no matter how smoothly the setup and the show ran, no matter how many visitors you had at your booth, if your presence at a show didn't net you any sales, then your considerable investment of time, money, and effort has been wasted.

The effect of the lubrication regime on gear performance has been recognized, qualitatively, for decades. Often the lubrication regime is characterized by the specific film thickness defined as the ratio of lubricant
film thickness to the composite surface roughness. It can be difficult to combine results of studies to create a cohesive and comprehensive data set. In this work gear surface fatigue lives for a wide range of specific film values were studied using tests done with common rigs, speeds, lubricant temperatures, and test procedures.

The object of any business transaction, be it foreign or domestic, is making a profit. That's why you go through all the effort of making and selling your product in the first place. Getting paid in a timely manner is crucial to making profit, but when your customer is in another country, this "timely and convenient" payment can become complicated; hence, your need for a banker with expertise in international markets.

Could the tip chamfer that manufacturing people usually use on the tips of gear teeth be the cause of vibration in the gear set? The set in question is spur, of 2.25 DP, with 20 degrees pressure angle. The pinion has 14 teeth and the mating gear, 63 teeth. The pinion turns at 535 rpm maximum. Could a chamfer a little over 1/64" cause a vibration problem?

In this issue of Gear Technology, we are focusing on using computers to their greatest advantage in gear design and manufacturing. In a sense, that's old news. It's a cliche to suggest that computers make our work life easier and more productive. No company that wishes to remain competitive in today's global manufacturing environment can afford to be without computers in all their manifestations. We need them in the office; we need them next to our desks in place of drafting boards; we need them on the shop floor.

Pretty much everyone
old enough to utter the
familiar, dual syllabic refrain of “beep boop” in the electro-mechanical,
monotone pitch from every sci-fi movie ever made has the same idea of what a
robot looks likes.

Two items of interest have crossed my desk in the last couple of weeks. One of them is a copy of a speech by Harry E. Figge, Jr., Chairman and CEO of Figge, International Inc., and the other is an article by Peter Brimelow in the July 19, 1993, issue of Forbes. The two items are directly related to one another, the Brimelow article being a response to the points raised in Figge's speech and in much grater detail in his book, Bankruptcy 1995: The Coming Collapse of America and How to Stop It. Both the speech and the response are well worth our attention.

Putting one's best foot forward is important for successful business communication. And successful business people know the "rule" of the game, what it say and do in business situations, to make the best impression. However, these rules change from country to country, and what is appropriate behavior here may appear rude to someone from Latin America, Europe or Asia To help you become more familiar with some of the different rules of engagement in other countries, Gear Technology spoke with three businessmen who have had extensive contact in various part of the world.

Optimization is applied to the design of a spiral bevel gear reduction for maximum life at a given size. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial values. Gear tooth bending strength and minimum contact ration under load are included in the active constraints. The optimal design of the spiral bevel gear reduction includes the selection of bearing and shaft proportions in addition to gear mesh parameters. System life is maximized subject to a fixed back-cone distance of the spiral bevel gear set for a specified speed ratio, shaft angle, input torque and power. Significant parameters in the design are the spiral angle, the pressure angle, the numbers of teeth on the pinion and gear and the location and size of the four support bearings. Interpolated polynomials expand the discrete bearing properties and proportions into continuous variables for gradient optimization. After finding the continuous optimum, a designer can analyze near-optimal designs for comparison and selection. Design examples show the influence of the bearing lives on the gear parameters in the optimal configurations. For a fixed back-cone distance, optimal designs with larger shaft angles have larger service lives.

The aim of this article is to show a practical procedure for designing optimum helical gears. The optimization procedure is adapted to technical limitations, and it is focused on real-world cases. To emphasize the applicability of the procedure presented here, the most common optimization techniques are described. Afterwards, a description of some of the functions to be optimized is given, limiting parameters and restrictions are defined, and, finally, a graphic method is described.

The working surfaces of gear teeth are often the result of several machining operations. The surface texture imparted by the manufacturing process affects many of the gear's functional characteristics. To ensure proper operation of the final assembly, a gear's surface texture characteristics, such as waviness and roughness, can be evaluated with modern metrology instruments.

CNC technology offers new opportunities for the manufacture of bevel gears. While traditionally the purchase of a specific machine at the same time determined a particular production system, CNC technology permits the processing of bevel gears using a wide variety of methods. The ideological dispute between "tapered tooth or parallel depth tooth" and "single indexing or continuous indexing" no longer leads to an irreversible fundamental decision. The systems have instead become penetrable, and with existing CNC machines, it is possible to select this or that system according to factual considerations at a later date.

The acceptance by discerning customers of passenger cars is dependent upon both the actual noise lever and the subjective noise character.
The subjective noise character itself can contain, among other features, undesirable noise phenomena which become apparent at certain points in the vehicle operating range. One such critical phenomenon is gear rattle, which is mainly present under low speed, high load conditions. Due to changes in the angular velocity of the crankshaft, gear rattle under driving conditions occurs at the unloaded gears and splines.

From time to time, the editors of "Shop Floor" receive correspondence from readers relating to particular articles they have written for past issues. As one of the purposes of this column is to provide a forum for the exchange of ideas, we reproduce here two of these letters and their replies. The subject of the first is the functional measurement of gears. (See Gear Technology, Sept/Oct, 1991, p. 17) Robert E. Smith writes the reply.

One of our readers in England has asked for our help in locating published technical data and information on the design, manufacture, and inspection of camshaft gears. Although millions of these gears have been made and are in constant use, we are not aware of any formal material having been published. We would be pleased to hear from anyone who had knowledge of such information.

In the past gear manufacturers have had to rely on hob manufacturers' inspection of individual elements of a hob, such as lead, involute, spacing, and runout. These did not always guarantee correct gears, as contained elements may cause a hob to produce gears beyond tolerance limits.

Worm gears are among the oldest types of gearing, but that does not mean they are obsolete, antiquated technology. The main reasons for the bad experiences some engineers have with worm gearing are misapplication and misuse. No form of gearing works for every application. Strengths and weaknesses versus the application must be weighed to decide which form of gearing to use. For proper application and operation of worm gears, certain areas that may differ from other types of gearing need to be addressed.

Given the current economic and legal climate, matters of hiring and firing are cause for considerable concern among managers. In addition to all the other factors to be considered, employers must be wary of exactly how these procedures should be carried out, so that the company is not left open to lawsuits based on charges of discrimination of one kind or another. The reasons given for a particular employment decision may be as crucial to determining liability as the decision itself.

Power train designs which employ gears with cone angles of approximately 2 degrees to 5 degrees have become quite common. It is difficult, if not impossible, to grind these gears on conventional bevel gear grinding machines. Cylindrical gear grinding machines are better suited for this task. This article will provide an overview of this option and briefly introduce four grinding variation possibilities.

Environmentally friendly, highly efficient and lasting a product's lifetime. With characteristics like this, Pulsed-Plasma Diffusion (PPD) technology from Oerlikon Balzers has established itself as an industry standard for the treatment of large automotive press tooling. Now the technology specialists are targeting new applications with this advanced process, offering an alternative to traditional hard-chrome processes.

Happy days are here again, says the old song, and given the current economic numbers, one can scarcely argue. Productivity is up; unemployment is down; inflation is practically nonexistent; the budget deficit is shrinking fast.

A programmable algorithm is developed to separate out the effect of eccentricity (radial runout) from elemental gear inspection date, namely, profile and lead data. This algorithm can be coded in gear inspection software to detect the existence, the magnitude and the orientation of the eccentricity without making a separate runout check. A real example shows this algorithm produces good results.

It is widely recognized that the reduction of CO2 requires consistent
light-weight design of the entire vehicle. Likewise, the trend towards electric cars requires light-weight design to compensate for the additional weight of battery systems. The need for weight reduction is also present regarding vehicle transmissions. Besides the design of the gearbox housing, rotating masses such as gear wheels and shafts have a significant impact on fuel consumption. The current technology shows little potential of gear weight reduction due to the trade-off between mass optimization and the manufacturing process. Gears are usually forged followed or not by teeth cutting operation.

Composite spur gears were designed, fabricated and tested at NASA Glenn Research Center. The composite web was
bonded only to the inner and outer hexagonal features that were machined from an initially all-metallic aerospace quality spur gear. The hybrid gear was tested against an all-steel gear and against a mating hybrid gear. Initial results indicate that this type of hybrid design may have a dramatic effect on drive system weight without sacrificing strength.

The hob is a perfect example of how a little manufacturing ingenuity can make a reliable, highly productive cutting tool. It's an engineering specimen
that creates higher cutting speeds, better wear resistance and increases rigidity. The cutting tool alone, however, can't take all the credit for its resourcefulness. Advanced coating
technology from companies like Sulzer, Oerlikon Balzers, Ionbond, Seco Tools and Cemecon helps improve cutting tools by reducing overall costs, increasing tool life and maintaining the highest levels of productivity. The following is a quick recap of new technologies
and the latest information in the coating market.

The research presented here is part of an ongoing (six years to date) project of the Cluster of Excellence (CoE). CoE is a faculty-wide group of researchers from RWTH Aachen University in Aachen (North Rhine-Westphalia). This presentation is a result of the group’s examination of "integrative production technology for high-wage countries," in which a shaft for a dual-clutch gearbox is developed.

Fig. 1 shows the effects of positive and negative rake on finished gear teeth. Incorrect positive rake (A) increase the depth and decreases the pressure angle on the hob tooth. The resulting gear tooth is thick at the top and thin at the bottom. Incorrect negative rake (B) decreases the depth and increases the pressure angle. This results in a cutting drag and makes the gear tooth thin at the top and thick at the bottom.

Although a cell is dedicated to produce a single part family, it must have the requisite equipment capabilities, routing flexibility, cross-trained employees and, to the extent possible, minimal external process dependencies. Cells are often implemented in job shops since they provide the operational benefits of flowline production.

Bevel gears must be assembled in a specific way to ensure smooth running and optimum load distribution between gears. While it is certainly true that the "setting" or "laying out" of a
pair of bevel gears is more complicated than laying out a pair of spur gears, it is also true that following the correct procedure can make the task much easier. You cannot install bevel gears in the same manner as spur and helical gears and expect them to behave and perform as well; to optimize the performance of any two bevel gears, the gears must be positioned together so that they run smoothly without binding and/or excessive backlash.

The present article contains a preliminary description of studies carried out by the authors with a view toward developing asymmetrical gear teeth. Then a comparison between numerous symmetrical and asymmetrical tooth stress fields under the same modular conditions follows. This leads to the formulation of a rule for similar modules governing variations of stress fields, depending on the pressure angle of the nonactive side. Finally a procedure allowing for calculations for percentage reductions of asymmetrical tooth modules with respect to corresponding symmetrical teeth, maximum ideal stress being equal, is proposed. Then the consequent reductions in size and weight of asymmetrical teeth are assessed.

Several articles have appeared in this publication in recent years dealing with the principles and ways in which the inspection of gears can be carried out, but these have dealt chiefly with spur, helical and bevel gearing, whereas worm gearing, while sharing certain common features, also requires an emphasis in certain areas that cause it to stand apart. For example, while worm gears transmit motion between nonparallel shafts, as do bevel and hypoid gears, they usually incorporate much higher ratios and are used in applications for which bevel would not be considered, including drives for rotary and indexing tables in machine tools, where close tolerance of positioning and backlash elimination are critical, and in situations where accuracy of pitch and profile are necessary for uniform transmission at speed, such as elevators, turbine governor drives and speed increasers, where worm gears can operate at up to 24,000 rpm.

"Going green" and energy efficiency are goals that all industries -- especially in Europe and the United States -- are working on, in such sectors as electric motors, lubrication, gears and on and on. Drumroll here please for magnetic gearing

Gleason Corporation has announced that agreement has been reached on all terms to acquire for approximately $36 million in cash the Hermann Pfauter Group, including, among other operations, Hermann Pfauter GmbH & Co., a privately held leading producer of gear equipment based in Ludwigsburg, Germany; its 76% interest in Pfauter-Maad Cutting Tools, a leading cutting tool manufacturer basked in Loves Park, IL; and Pfauter-Maag management's 24% ownership interest in that company. The acquisition includes all assets and liabilities, including the assumption of approximately $56 million in bank debt.

Job shops may be ill-advised to undertake a complete reorganization into FLEAN (Flexible and Lean) cells. A FLEAN cell would (i) be flex-ible enough to produce any and all orders for parts that belong in a specific part family and (ii) utilize lean to the maximum extent possible to eliminate waste.

No one (not even you and I) consistently makes parts with perfect form and dimensions, so we must be able to efficiently check size and shape at many stages in the manufacturing and assembly process to eliminate scrap and rework and improve processes and profits. Automated inspection systems, which are widely used in all kinds of manufacturing operations, provide great efficiencies in checking individual features, but may not be as effective when asked to evaluate an entire part. You need to know why this is true and what you can do to improve your part yields.

It's nice to see old friends. It's also advantageous to make new ones. Gear Expo has always been a family reunion of sorts, but it's first and foremost an opportunity to show off the latest and greatest technologies that are impacting the gear industry today. With this in mind, Gear Technology recently spoke with those responsible for putting the Fall Technical Meeting (FTM) and Gear Expo 2013 together in Indianapolis.

A fundamental characteristic of the gear industry is that it is capital intensive. In the last decade, the gear manufacturing industry has been undergoing an intense drive toward improving and modernizing its capital equipment base. The Department of Commerce reports that annual sales of gear cutting equipment have increased nearly 60% since 1990. While this effort has paid off in increased competitiveness for the American gear industry, it is important to remember that there is another capital crucial to manufacturing success - "human capital."

It should be obvious by now that gears are more than just mechanical components. We have brought you movies with gears and Shakespeare with gears, jewelry made out of gears and so on. Now we, the humble staff at Addendum, are proud to present gears in the world of music.

The gear industry lost one of its iconic figures in July when James Cervinka passed away at the age of 92. Jim was CEO and one of the founders of Arrow Gear. For 65 years, he was a gear man, and I can’t help but feeling that his absence shrinks the gear industry by far more than the loss of just one man.

Understanding the morphology of micropitting is critical in determining the root cause of failure. Examples of micropitting in gears and rolling-element bearings are presented to illustrate morphological variations that can occur in practice.

Romax Technology, the gearbox, bearing
and driveline engineering specialist, has launched a new design software package that will increase speed, quality, creativity and innovation when designing gearboxes and drivelines. Called Concept, the new product delivers on the Romax vision of streamlining the end-to-end, planning-to-manufacture process with open, easy to use software solutions. It has been developed in close collaboration with engineers in the largest ground vehicle, wind energy and industrial
equipment companies around the globe.

By increasing the number of gears and the transmission-ratio spread, the engine will run with better fuel
efficiency and without loss of driving
dynamics. Transmission efficiency
itself can be improved by: using fuelefficient transmission oil; optimizing the lubrication systems and pumps; improving shifting strategies and optimizing gearings; and optimizing bearings and seals/gaskets.

In the August issue, we examined the lean tools that will and will not work in high-mix, low-volume manufacturing facilities. Now, we will examine how to implement the tools that will work in the job shop with an approach that expands the capabilities of value stream mapping.

This article discusses the relationships among the fillet stress on a thin rim planet gear, the radial clearance between the gear rim and the gear shaft, the tooth load, the rim thickness, the radius of curvature of the center line of the rim, the face width and the module.

the gear industry is awash in manufacturing technologies that promise to eliminate waste by producing gears in near-net shape, cut production and labor costs and permit gear designers greater freedom in materials. These methods can be broken down into the following categories: alternative ways to cut, alternative ways to form and new, exotic alternatives. Some are new, some are old and some are simply amazing.

Let's face it. The Internet is still, to many of us, exciting, confusing, terrifying and frustrating by turns. The buzzwords change so fast that even the most high tech companies have a hard time keeping up. Cyberspace. Firewall, Java. E-commerce. The list goes on.

Come with us now to those thrilling days of yesteryear...Ok, this is not the Cisco Kid, but we do have a little game for you. Guess the year the following advertisements and excerpt were printed - they all appeared in a dingle issue of Machinery Magazine.

In the last section, we discussed gear inspection; the types of errors found by single and double flank composite and analytical tests; involute geometry; the involute cam and the causes and symptoms of profile errors. In this section, we go into tooth alignment and line of contact issues including lead, helix angles, pitch, pitchline runout, testing and errors in pitch and alignment.

It is very common for those working in the gear manufacturing industry to have only a limited understanding of the fundamental principals of involute helicoid gear metrology, the tendency being to leave the topic to specialists in the gear lab. It is well known that quiet, reliable gears can only be made using the information gleaned from proper gear metrology.

Move over, Michael Jordan. While the Addendum staff is as proud as any other Chicagoans of our unbeata-Bulls, we confess to a soft spot in our hearts for the hometown's other championship basketball team: The Chicago American Gears.

AGMA has an excellent Training School for Gear Manufacturing. It's a great product providing a great service to the gear industry. Thus far we've educated 117 employees from 71 companies; students range from new hires with no experience to company presidents. Essentially every class since December, 1992, has been sold out.

In recent years, gear inspection requirements have changed considerably, but inspection methods have barely kept pace. The gap is especially noticeable in bevel gears, whose geometry has always made testing them a complicated, expensive and time-consuming process. Present roll test methods for determining flank form and quality of gear sets are hardly applicable to bevel gears at all, and the time, expense and sophistication required for coordinate measurement has limited its use to gear development, with only sampling occurring during production.

You've been reading about it, talking about it, maybe even trying it. Gear Technology has jumped aboard it feet first and begun a voyage on the World Wide Web. Beginning with this issue, an electronic version of the magazine will be online. For those of us who still find the fax machine amazing technology, this is a great leap.

Light-weight construction and consideration of available resources result in gearbox designs with high load capacity and power density. At the same time, expectations for gear reliability are high. Additionally, there is a diversity of planetary gears for different applications.

The data discussed in this article was taken from an upright vacuum cleaner. This was a prototype cleaner that was self-propelled by a geared transmission. It was the first time that the manufacturer had used a geared transmission in this application.

Part I of this paper describes the theory behind double-flank composite inspection, detailing the apparatus used, the various measurements that can be achieved using it, the calculations involved and their interpretation. Part II, which will appear in the next issue, includes a discussion of the practical application of double-flank composite inspection, especially for large-volume operations. Part II covers statistical techniques that can be used in conjunction with double-flank composite inspection, as well as an in-depth analysis of gage R&R for this technique.

The purpose of this article is to clarify some terms and methods used in measuring the size of gears. There is also an explanation given of the error induced and how to correct for it in certain cases when the measurement is made using pins instead of balls.

There's nothing like a new year - with the possible exception of birthdays ending in zero - to remind one of the passage of time. Keeping track of time has always been part of the brief of the gear engineer. One of the earliest gear assemblies is the remains of the Antikythera machine, a calendar/calculator dating from the first century B.C. Until the industrial revolution, clock makers and gear designers were usually the same people.

221B Baker Street
We've always said that gears show up in all the best places, even, it turns out, among the papers of that most famous of detectives, Sherlock Holmes. "The Adventure of the Engineer's Thumb" is, according to Dr. Watson, a case "so strange in its inception and so dramatic in its details," that it merits a mention even in our exalted pages.

There are problems in dimensional measurement that should be simple to solve with standard measuring procedures, but aren't. In such cases, using accepted practices may result in errors of hundreds of microns without any warning that something is wrong.

In today's industrial marketplace, deburring and chamfering are no longer just a matter of cosmetics. The faster speeds at which transmissions run today demand that gear teeth mesh as smoothly and accurately as possible to prevent premature failure. The demand for quieter gears also requires tighter tolerances. New heat treating practices and other secondary gear operations have placed their own set of demands on manufacturers. Companies that can deburr or chamfer to these newer, more stringent specifications - and still keep costs in line - find themselves with a leg up on their competition.

Tiger stripes on a high-speed pinion made of a carburized SAE 9310 steel were investigated. The morphology of the damage was typical of electric discharge damage. The cause of the stripes and potential damage to the gear tooth were analyzed and are presented in this report.

Part I of this paper, which appeared in the January/February issue of Gear Technology, described the theory behind double-flank composite inspection. It detailed the apparatus used, the various measurements that can be achieved using it, the calculations involved and their interpretation. The concluding Part II presents a discussion of the practical application of double-flank composite inspection -- especially for large-volume operations. It also addresses statistical techniques that can be used in conjunction with double-flank composite inspection, as well as an in-depth analysis of gage R&R for this technique.

Gears are manufactured with thin rims for several reasons. Steel gears are manufactured with thin rims and webs where low weight is important. Nonmetallic gears, manufactured by injection molding, are designed with thin rims as part of the general design rule to maintain uniform thickness to ensure even post-mold cooling. When a thin-rimmed gear fails, the fracture is thought the root of the gear, as shown in Fig. 1a, rather than the usual fillet failure shown in Fig. 1b.

Introducing backlash into spline couplings has been common practice in order to provide for component eccentric and angular misalignment. The method presented here is believed to be exact for splines with even numbers of teeth and approximate for those with odd numbers of teeth. This method is based on the reduction of the maximum effective tooth thickness to achieve the necessary clearance. Other methods, such as tooth crowning, are also effective.

Your Addendum team has come across a number of Good Ole Boys in its time; now we bring you something of even more interest - a Good Ole Gear Book. Mr. Robert Price, of Automation - Gears - Machinery, a gear consulting firm in Delanson, NY, shared with us a real find.

The diagnosis and prevention of gear tooth and bearing wear requires the discovery and understanding of the particular mechanism of wear, which in turn indicates the best method of prevention. Because a gearbox is a tribologically dependent mechanism, some understanding of gear and bearing tribology is essential for this process. Tribology is the general term for the study and practice of lubrication, friction and wear. If tribology is neglected or considered insignificant, poor reliability and short life will result.

When designing a gear set, engineers usually want the teeth of the gear (Ng) and the pinion (Np) in a "hunting" mesh. Such a mesh or combination is defined as one in which the pinion and the gear do not have any common divisor by a prime number. If a mesh is "hunting," then the pinion must make Np x Ng revolutions before the same pinion tooth meshes with the same gear space. It is often easy to determine if a mesh is hunting by first determining if both the pinion and the gear teeth are divisible by 2,3,5,7,etc. (prime numbers). However, in this age of computerization, how does one program the computer to check for hunting teeth? A simple algorithm is shown below.

When you need totally useless information about gears, you can turn with confidence to the pages of Addendum, where we scour the globe for the obscure, the unusual and the ridiculous (the latter being or forte.)

Recent advances in spiral bevel gear geometry and finite element technology make it practical to conduct a structural analysis and analytically roll the gear set through mesh. With the advent of user-specific programming linked to 3-D solid modelers and mesh generators, model generation has become greatly automated. Contact algorithms available in general purpose finite element codes eliminate the need for the use and alignment of gap elements. Once the gear set it placed in mesh, user subroutines attached to the FE code easily roll it through mesh. The method is described in detail. Preliminary result for a gear set segment showing the progression of the contact line load is given as the gears roll through mesh.

Design Problem: Develop a gear drive for a pedal-powered water craft that will be easy to manufacture, use and maintain; that will be lightweight enough for the boat to be portable; and that will eliminate the environmental risk of lubricants leaking into the water.

Recently I had the pleasure of having dinner with Frank Sinatra, Jr. He was here in Chicago for a benefit concert for Roosevelt University (my wife is co-chairperson of the benefit). Our conversation ranged over a wide variety of subjects, including a small gem of an HBO television movie, "Truman" with Gary Sinise in the title role.

In the summer of 1974, long before Argo, there was “AZORIAN” -- the
code name for a CIA gambit to recover cargo entombed in a sunken Soviet submarine -- the K-129 -- from the bottom of the Pacific Ocean. The challenge: exhume -- intact -- a 2,000-ton submarine and its suspicious cargo from 17,000 feet of water.

What is a quality product? This is not an idle question. In the Darwinian business world in which we operate, knowing the answer to this question is key to our survival. A whole library of standards and benchmarks is available to help us gage how we're doing, but they don't really tell the whole story.

This article illustrates a structural analysis of asymmetrical teeth. This study was carried out because of the impossibility of applying traditional calculations to procedures involved in the specific case. In particular, software for the automatic generation of meshes was devised because existing software does not produce results suitable for the new geometrical model required. Having carried out the structural calculations, a comparative study of the stress fields of symmetrical and asymmetrical teeth was carried out. The structural advantages of the latter type of teeth emerged.

Rotary gear honing is a crossed-axis, fine, hard finishing process that uses pressure and abrasive honing tools to remove material along the tooth flanks in order to improve the surface finish (.1-.3 um or 4-12u"Ra), to remove nicks and burrs and to change or correct the tooth geometry. Ultimately, the end results are quieter, stronger and longer lasting gears.

There is a great need for future powertrains in automotive and industrial applications to improve upon their efficiency and power density while reducing their dynamic vibration and noise initiation. It is accepted that planetary gear transmissions have several advantages in comparison to conventional transmissions, such as a high power density due to the power division using several planet gears. This paper presents planetary gear transmissions, optimized in terms of
efficiency, weight and volume.

In July of 1996 we introduced the gear community to the Internet in these pages through the Gear Industry Home Page (GIHP). This electronic buyers guide for gear machine tools, tooling, accessories and services has proven to be more popular than we could have envisioned. In our first month, we had over 3,000 hits, and in our third month, we have over 4,500. By our fourth month, we topped the 7,000 mark, and we are on our way to 11,000 hits in November. As our advertisers develop their own home sites in order to offer layers of information about their companies, their products and services, we expect this activity will increase even more.

This article summarizes the development of an improved titanium nitride (TiN) recoating process, which has, when compared to conventional recoat methods, demonstrated tool life increases of up to three times in performance testing of hobs and shaper cutters. This new coating process, called Super TiN, surpasses the performance of standard TiN recoating for machining gear components. Super TiN incorporates stripping, surface preparation, smooth coating techniques and polishing before and after recoating. The combination of these improvements to the recoating process is the key to its performance.

In our unceasing attempt to further educate our readers - and find new and creative ways to waste time at work - the Addendum staff has spent many long hours (and many dollars on popcorn) to bring you our latest research on gears in film.

When is a gear not a gear? Pardon my Zen, but that is a bit like asking, "What is the sound of one hand clapping?" Or there’s the old bromide, "If it walks like a duck, talks like a duck," etc.
Just work with me here…

The chamfering and deburring operations on gear teeth have become more important as the automation of gear manufacturing lines in the automotive industry have steadily increased. Quieter gears require more accurate chamfers. This operation also translates into significant coast savings by avoiding costly rework operations. This article discusses the different types of chamfers on gear teeth and outlines manufacturing methods and guidelines to determine chamfer sizes and angles for the product and process engineer.

Physical Vapor Deposited (PVD) coatings such as TiN (Titanium nitride) have been a boon for cutting tool manufacturers. They reduce wear and, therefore, extend tool life, which in turn reduces production costs. But PVD coatings are expensive, and when they fail, they cost both time and money, and they causes of the failure are not always readily apparent.

If you've been following this space with any regularity, you know that grassroots efforts among industry and academia are springing up around the
country to help win the hearts, minds and talents of young people in nudging them towards a career in manufacturing. Add another partnership to the list.

Wave generators are located inside of flexsplines in most harmonic gear drive devices. Because the teeth on the wheel rim of the flexspline are distributed
radially, there is a bigger stress concentration on the tooth root of the flexspline meshing with a circular spline, where a fatigue fracture is more likely to occur under the alternating force exerted by the wave generator. The authors' solution to this problem is to place the wave generator outside of the flexspline, which is a scheme named harmonic
gear drive (HGD) with external wave generator (EWG).

Vibration and noise from wind turbines can be significantly influenced - and therefore reduced - by selecting suitable gearing modifications. New options provided by manufacturers of machine tools and grinding machines, and especially state-of-the-art machines and controls, provide combined gearing modifications - or topological gearing corrections - that can now be reliably machined. Theoretical investigations of topological modifications are discussed here with the actual machining and their possible use.

Gears are designed to be manufactured, processed and used without failure throughout the design life of the gear. One of INFAC's objectives (*see p.24) is to help manufacture of gears to optimize performance and life. One way to achieve this is to identify failure mechanisms and then devise strategies to overcome them by modifying the manufacturing parameters.

Point-surface-origin (PSO) macropitting occurs at sites of geometric stress concentration (GSC) such as discontinuities in the gear tooth profile caused by micropitting, cusps at the intersection of the involute profile and the trochoidal root fillet, and at edges of prior tooth damage, such as tip-to-root interference. When the profile modifications in the form of tip relief, root relief, or both, are inadequate to compensate for deflection of the gear mesh, tip-to-root
interference occurs. The interference can occur at either end of the path of contact, but the damage is usually more
severe near the start-of-active-profile (SAP) of the driving gear.

A series of bench-top experiments was conducted to determine the effects of metallic debris being dragged through meshing gear teeth. A test rig that is typically used to conduct contact fatigue experiments was used for these tests. Several sizes of drill material,
shim stock and pieces of gear teeth were introduced and then driven through the meshing region. The level of torque required to drive the “chip” through the gear mesh was measured. From the data gathered, chip size sufficient to jam the mechanism can be determined.

Hobs, broaches, shaper cutters,
shaver cutters, milling cutters,
and bevel cutters used in the
manufacture of gears are commonly
made of high speed steel. These specialized gear cutting tools often require properties, such as toughness or manufacturability, that are difficult to achieve with carbide, despite the developments in carbide cutting tools for end mills, milling cutters, and tool inserts.

This article is part four of an eight-part series on the tribology aspects of angular gear drives. Each article will be presented first and exclusively by Gear Technology, but the entire series will be included in Dr. Stadtfeld’s upcoming book on the subject, which is scheduled for release in 2011.

In this paper a new method for the introduction of optimal modifications into gear tooth surfaces—based on the
optimal corrections of the profile and diameter of the head cutter, and optimal variation of machine tool settings for pinion and gear finishing—is presented. The goal of these tooth modifications is the achievement of a more favorable
load distribution and reduced transmission error. The method is applied to face milled and face hobbed hypoid gears.

At its location in Roscoe, IL, the Forest City Gear facility is surrounded by wildlife splendor. Fruit trees, nature walks and the occasional cute and furry animal sighting create an unlikely landscape for a manufacturing site. Of course, cavorting with the cute and furry does have its drawbacks.

With growing markets in aerospace and energy technologies, measuring hob cutters used in gear cutting is becoming an essential requirement for workpieces and machine tools. Zoller, a provider of solutions for tool pre-setters, measuring and inspection
machines and tool management software,
has developed a new partnership with Ingersoll/Germany for shop floor
checking of hob cutters by a combined
hardware and software approach.

Surface coatings or finishing processes are the future technologies
for improving the load carrying capacity of case hardened gears. With
the help of basic tests, the influence of different coatings and finishing
processes on efficiency and resistance to wear, scuffing, micropitting,
and macropitting is examined.

Gear designs are evolving at an ever accelerating rate, and gear manufacturers need to better understand
how the choice of materials and heat treating methods can optimize mechanical properties, balance overall cost and extend service life.

This paper shows an experimental study on the fatigue lifetime of high-heat polyamide (Stanyl) gears running in oil at 140°C. Based on previous works (Refs. 1–2), an analysis is made correcting for tooth bending and calculating actual root stresses. A comparison with tensile bar fatigue data for the same materials at 140°C shows that a good correlation exists between gear fatigue data and tensile bar fatigue data. This insight provides a solid basis for gear
designers to design plastic gears using actual material data.

Several innovations have been introduced to the gear manufacturing industry in recent years. In the case of gear hobbing—the dry cutting technology and the ability to do it with powder-metallurgical HSS—might be two of the most impressive ones. And the technology is still moving forward. The aim of this article is to present recent developments in the field of gear hobbing in conjunction with the latest improvements regarding tool materials, process technology
and process integration.

Easily one of the central issues
affecting U.S. manufacturing is what one might call the exports deficit—the inability of American companies to sell products to, for instance, Asian markets, developing countries and other ports of call—due to what they perceive to be unfair trade agreements and or policies.

Gear metrology is a revolving door of software packages and system upgrades. It has to be in order to keep up with the productivity and development
processes of the machines on the
manufacturing floor. Temperature
compensation, faster inspection times
and improved software packages are
just a few of the advancements currently in play as companies prepare for new opportunities in areas like alternative energy, automotive and aerospace/defense.

Profile corrections on gears are a commonly used method to reduce transmission error, contact shock, and scoring risk. There are different types of profile corrections. It is a known fact that the type of profile correction used will have a strong influence on the resulting transmission error. The degree of this influence may be determined by calculating tooth loading during mesh. The current method for this calculation is very complicated and time consuming; however,
a new approach has been developed that could reduce the calculation time.

In the August 2008 issue of Gear Technology, we ran a story (“Gearbox
Speed Reducer Helps Fan Technology for ‘Greener” Jet Fuel Efficiency’) on the
then ongoing, extremely challenging and protracted development of Pratt
& Whitney’s geared turbofan (GTF) jet engine.

This paper presents an original method to compute the loaded mechanical behavior of polymer gears. Polymer
gears can be used without lubricant, have quieter mesh, are more resistant to corrosion, and are lighter in weight.
Therefore their application fields are continually increasing. Nevertheless, the mechanical behavior of polymer materials is very complex because it depends on time, history of displacement and temperature. In addition, for several polymers, humidity is another factor to be taken into account. The particular case of polyamide 6.6 is studied in this paper.

This paper presents an approach that provides optimization of both gearbox kinematic arrangement and gear tooth geometry to achieve a high-density gear transmission. It introduces dimensionless gearbox volume functions that can be minimized by the internal gear ratio optimization. Different gearbox arrangements are analyzed to define a minimum of the volume functions. Application of asymmetric gear tooth profiles for power density
maximization is also considered.

The connection between transmission error, noise and vibration during operation has long been established.
Calculation methods have been developed to describe the influence so that it is possible to evaluate the relative effect
of applying a specific modification at the design stage. These calculations enable the designer to minimize the excitation from the gear pair engagement at a specific load. This paper explains the theory behind transmission error and the reasoning behind the method of applying the modifications through mapping surface profiles and determining load sharing.

The approximate tensile strength of any steel is measured by its hardness, Table 1. Since hardness is determined by both
chemical composition and heat treatment, these are the two important metallurgical considerations in selecting gear steels.

While on holiday in England during July, my thoughts for this page were on the proposed changes to our tax law, and how they would adversely affect America's industry. But with the President undergoing cancer surgery, Congress deadlocked on deficit reduction and the budget on the back burner, nothing new was being said or done regarding a new tax law

Borazon is a superabrasive material originally developed by General Electric in 1969. It is a high performance material for machining of high alloy ferrous and super alloy materials. Borazon CBN - Cubic Born Nitride - is manufactured with a high temperature, high pressure process similar to that utilized with man-made diamond. Borazon is, next to diamond, the hardest abrasive known; it is more than twice as hard as aluminum oxide. It has an extremely high thermal strength compared to diamond. It is also much less chemically reactive with
iron, cobalt or nickel alloys.

A brief introduction to the subject of Thin Film Coatings and their application to gear hobs and shaper cutters is followed by a detailed description of the Chemical Vapor Deposition Process and the Physical Vapor Deposition Process. Advantages and disadvantages of each of these processes is discussed. Emphasis is placed upon: application engineering of coated gear tools based on laboratory and field test results. Recommendations are suggested for tool design improvements and optimization of gear cutting operations using coated tools. Productivity improvements potentially available by properly utilizing
coated tools are considered in terms of both tool cost and machining cost.

The objective, according to Dr.-
Ing. Hansjörg Geiser, head of development and design for gear machines at Liebherr, was to develop and design a combined turning and hobbing machine in which turning, drilling and hobbing work could be carried out in the same clamping arrangement as the hobbing of the gearings and the subsequent chamfering and deburring processes.

In response to Ed Uberts letter, we have come a long way in gearing since WWII. The Europeans do use long
addendum pinions in many cases. This modification does improve load capacity, sliding conditions and the working life of a gearset. When modifying a pinion tooth it is
necessary to modify the gear tooth or adjust the center distance accordingly but we will leave that to the designers.

Make no mistake -- lean manufacturing is here to stay. And no wonder. As a fiercely competitive global economy continues to alter companies’ “Main Street” thinking, that relatively new dynamic is spurring the need for “I-need-it-yesterday” production output. And for increasingly more industries -- big or small -- that means getting as lean as you can, as fast as you can.

Once upon a time there was a computer. This computer served as a conduit to waste a great deal of time through social networking and online video
games. Still, there was always potential to turn these rather sedentary activities into something
more positive and useful to mankind. Siemens may have stumbled upon such a concept.

Gears with an asymmetric involute gear tooth form were analyzed to determine their bending and contact stresses
relative to symmetric involute gear tooth designs, which are representative of helicopter main-drive gears.

In this study, limiting values for the load-carrying-capacity of fine-module gears within the module range 0.3–1.0 mm were determined and evaluated by comprehensive, experimental investigations that employed technical, manufacturing and material influence parameters.

This paper presents how low pressure carburizing and high pressure gas quenching processes are successfully applied on internal ring gears for a six-speed automatic transmission. The specific challenge in the heat treat process was to reduce distortion in such a way that subsequent machining operations are entirely eliminated.

The October 2011 issue of Gear Technology featured the article “Low-Distortion Heat Treatment of Transmission Components,” which covered
the combination of low-pressure
carburizing and high pressure gas quenching in an automotive environment. Here, heat treating expert Dan Herring explains why oil quenching is an appropriate choice for many applications.

When you push 850 horsepower and 9,000 rpm through a racing transmission, you better hope it stands up. Transmission cases and gears strewn all over the racetrack do nothing to enhance your standing, nor that of your transmission supplier.

A gearbox that absorbs 30 percent of external forces, transmits power from two engines operating at different speeds, and uses gears that meet several design and specification standards at the same time...

For a high-speed gearbox, an important part of power losses is due to the mesh. A global estimation is not possible and an analytical approach is necessary with evaluations of three different origins of power losses: friction in mesh contact, gear windage and pumping effect between teeth.

A computational fluid dynamics (CFD) method is adapted, validated and applied to spinning gear systems with emphasis on predicting windage losses.
Several spur gears and a disc are studied. The CFD simulations return good agreement with measured windage power loss.

The effect of various lubricant factors on wormgear efficiency has been evaluated using a variety of gear types and conditions. In particular, the significant efficiency improvements
afforded by certain types of synthetic
lubricants have been investigated to determine the cause of these improvements. This paper describes broad wormgear testing, both in the
laboratory and in service, and describes the extent to which efficiency can be affected by
changes in the lubricant; the effects of viscosity, viscosity index improvers and, finally, synthetic lubricants are discussed. The work concludes that lubricant tractional properties
can play a significant role in determining gear efficiency characteristics.

With all the work in transmission development these days, the demand for automobile transmission gears should remain strong for several years, but suppliers will have to be as flexible as possible to keep up with the changes.

This paper describes the research and development of the first production gearbox with asymmetric tooth profiles for the TV7-117S turboprop engine. The paper also presents numerical design data related to development of this gearbox.

Lamentations continue—legitimately so—over the second-citizen status of manufacturing in the United States. The need undoubtedly continues for renewed support by government and educators for making things here once again...

This past fall, I had the opportunity to travel to Japan, Korea, Taiwan, and Singapore to witness first-hand the status of the power transmission and machine tool industries in these areas. Points of interest included equipment, material handling, computerization, wage and tax structures, inventory controls, and workforce attitude.

In the field of large power transmission gear units for heavy machine industry, the following two development trends have
been highly influential: use of case hardened gears and a branching of the power flow through two or more ways.

Everyone makes mistakes. Nobody's perfect. We've all heard those or similar words, and if you happen to be in charge of your company's quality efforts, you've probably heard them more than most people.

Austempering heat treatments
(austenitizing followed by rapid cooling
to the tempering temperature) have been
applied to nodular irons on an experimental basis for a number of years, but commercial interest in the process has
only recently come to the surface.

The gear tooth fillet is an area of maximum bending stress concentration. However, its profile is typically less specified in the gear drawing and hardly controlled during gear inspection in comparison with the gear tooth flanks. This paper presents a fillet profile optimization technique for gears with symmetric and asymmetric teeth based on FEA and a random search method. It allows achieving substantial bending stress
reduction in comparison with traditionally designed gears. This bending stress reduction can be traded for higher load capacity, longer lifetime, lower noise and vibration and cost reduction.

Gear engineers have long recognized the importance of considering system factors when analyzing a single pair of gears in mesh. These factors include important considerations
such as load sharing in multi-mesh geartrains and bearing clearances, in addition to the effects of flexible components such as housings, gear blanks, shafts and carriers for planetary geartrains. However, in recent years, transmission systems have become increasingly complex—with higher numbers of gears and components—while the quality requirements and expectations in terms of durability, gear whine, rattle and efficiency
have increased accordingly.

The proper control of distortion after thermal treatment of powertrain components in the automotive industry is an important measure in ensuring high-quality parts and minimizing subsequent hard machining processes in order to reduce overall production costs.

Big gears and wind turbines go together like bees and honey, peas and carrots, bread and butter and—well, you
get the idea. Wind isn’t just big right now, it’s huge. The wind industry means tremendous things for the energy dependent world we live in and especially big things for gear
manufacturers and other beleaguered American industries.

The load carrying behavior of gears is strongly influenced by local stress concentrations in the tooth root and by Hertzian pressure peaks in the tooth flanks produced by geometric deviations associated with manufacturing, assembly and deformation processes. The dynamic effects within the mesh are essentially determined by the engagement shock, the parametric excitation and also by the deviant tooth geometry.

Involute Curve Fundamentals. Over the years many different curves have been considered for the profile of a gear tooth. Today nearly every gear tooth uses as involute profile. The involute curve may be described as the curve generated by the end of a string that is unwrapped from a cylinder. (See Fig. 1) The circumference of the cylinder is called the base circle.

Although there is plenty of information and data on the determination of geometry factors and bending strength of external gear teeth, the computation methods regarding internal gear design are less accessible. most of today's designs adopt the formulas for external gears and incorporate some kind of correction factors for internal gears. However, this design method is only an approximation because of the differences between internal gears and external gears. Indeed, the tooth shape of internal gears is different from that of external gears. One has a concave curve, while the other has a convex curve.

Worm gear speed reducers give the design engineer considerable options, but these gear systems present a challenge to the lubrication engineer. Heat energy generated by the high rate of sliding and friction in the contact zone causes worm gears to be relatively inefficient compared to other gear types. Because worm gears operate under a boundary or near-boundary lubrication regime, a satisfactory lubricant should contain a friction modifier to alleviate these conditions.

In our last issue, the labels on the drawings illustrating "Involutometry" by Harlan Van Gerpan and C. Kent Reece were inadvertently omitted. For your convenience we have reproduced the corrected illustrations here. We regret any inconvenience this may have caused our readers.

Plane strain fracture toughness of twelve high-carbon steels has been evaluated to study the influence of alloying elements, carbon content and retained austenite. The steels were especially designed to simulate the carburized case microstructure of commonly used automotive type gear steels. Results show that a small variation in carbon can influence the K IC significantly. The beneficial effect of retained austenite depends both on its amount and distribution. The alloy effect, particularly nickel, becomes significant only after the alloy content exceeds a minimum amount. Small amounts of boron also appear beneficial.

Gears are toothed wheels used primarily to transmit motion and power between rotating shafts. Gearing is an assembly of two or more gears. The most durable of all mechanical drives, gearing can transmit high power at efficiencies approaching 0.99 and with long service life. As precision machine elements gears must be designed.

This article investigates fillet features consequent to tooth grinding by generating methods. Fillets resulting from tooth cutting and tooth grinding at different pressure angles and with different positions of grinding wheel are compared. Ways to improve the final fillet of the ground teeth with regard to tooth strength and noise, as well as the grinding conditions, are shown. "Undergrinding" is defined and special designs for noiseless gears are described.

Among the various types of gearing systems available to the gear application engineer is the versatile and unique worm and worm gear set. In the simpler form of a cylindrical worm meshing at 90 degree axis angle with an enveloping worm gear, it is widely used and has become a traditional form of gearing. (See Fig. 1) This is evidenced by the large number of gear shops specializing in or supplying such gear sets in unassembled form or as complete gear boxes. Special designs as well as standardized ratio sets covering wide ratio ranges and center distanced are available with many as stock catalog products.

Vehicle gear noise testing is a complex and often misunderstood subject. Gear noise is really a system problem.(1) most gearing used for power transmission is enclosed in a housing and, therefore, little or no audible sound is actually heard from the gear pair.(2) The vibrations created by the gears are amplified by resonances of structural elements. This amplification occurs when the speed of the gear set is such that the meshing frequency or a multiply of it is equal to a natural frequency of the system in which the gears are mounted.

Beveloid gears are used to accommodate a small shaft angle. The manufacturing technology used for beveloid gearing
is a special setup of cylindrical gear cutting and grinding machines. A new development, the so-called Hypoloid
gearing, addresses the desire of gear manufacturers for more freedoms. Hypoloid gear sets can realize shaft angles between zero and 20° and at the same time, allow a second shaft angle (or an offset) in space that provides the freedom to connect two points in space.

Noisy gear trains have been a common problem for gear designers for a long time. With the demands for smaller gear boxes transmitting more power at higher
rpms and incumbent demands for greater efficiency, gear engineers are always searching for new ways to reduce vibration and limit noise without increasing costs.

Inviting an American shipbuilding industry official to discuss the subject of meeting foreign competition is like inviting Jackie Gleason to speak on dieting. I am painfully aware of the commercial shipbuilding industry situation. Let me tell you a little about it.

Gear noise can be a source of intense annoyance. It is often the primary source of annoyance even when it is not the loudest noise component. This is because of the way it is perceived. Gear noise is a collection of pure tones which the human ear can detect even when they are 10dB lower than the overall noise level. Another reason for our sensitivity to transmission noise is that we associate it with impending mechanical failure.

The higher load carrying capacities, compact dimensions and longer life of hardened gears is an accepted fact in industry today. However, the costs involved in case hardening and subsequent finishing operations to achieve these advantages are considerable. For example, in order to achieve desired running properties on larger gears, it has been necessary to grind the tooth flanks. This costly operation can now be replaced, in many cases, by a new Hard Cutting (HC)
process which permits the cutting of hardened gears while maintaining extremely low tooling costs.

Circular arc helical gears have been proposed by Wildhaber and Novikov (Wildhaber-Novikov gears). These types of gears became very popular in the sixties, and many authors in Russia, Germany, Japan and the People's Republic of China made valuable contributions to this area. The history of their researches can be the subject of a special investigation, and the authors understand that their references cover only a very small part of the bibliography on this topic.

Almost all machines or mechanical systems contain precision contact elements such as bearings, cams, rears, shafts, splines and rollers. These components have two important common requirements: first, they must possess sufficient mechanical properties, such as, high hardness, fatigue strength and wear resistance to maximize their performance and life; second, they must be finished to close dimensional tolerances to minimize noise, vibration and fatigue loading.

The first commandment for gears reads "Gears must have backlash!" When gear teeth are operated without adequate
backlash, any of several problems may occur, some of which may lead to disaster. As the teeth try to force their way through mesh, excessive separating forces are created which
may cause bearing failures. These same forces also produce a wedging action between the teeth with resulting high loads on the teeth. Such loads often lead to pitting and to other failures related to surface fatigue, and in some cases, bending failures.

Recently, there has been increased interest in the dynamic effects in gear systems. This interest is stimulated by demands for stronger, higher speed, improved performance, and longer-lived systems. This in turn had stimulated numerous research efforts directed toward understanding gear dynamic phenomena. However, many aspects of gear dynamics are still not satisfactorily understood.

You get calls and letters every day from people wanting you to use their ad agency, their direct mail program, their p.r. or marketing firm to promote your business. It seems everyone wants you to spend your money to communicate to your prospects and customers. But what's the best method for you?

Carburized and hardened gears have optimum load-carrying capability. There are many alternative ways to produce a hard case on the gear surface. Also, selective direct hardening has some advantages in its ability to be used in the production line, and it is claimed that performance results equivalent to a carburized gear can be obtained. This article examines the alternative ways of carburizing, nitriding, and selective direct hardening, considering equipment, comparative costs, and other factors. The objective must be to obtain the desired quality at the lowest cost.

Non-uniform gear wear changes gear topology and affects the noise performance of a hypoid gear set. The
aggregate results under certain vehicle driving conditions could potentially result in unacceptable vehicle noise performance in a short period of time. This paper presents the effects of gear surface parameters on gear wear and the measurement/testing methods used to quantify the flank wear in laboratory tests.

When Belgium-based Hansen Transmissions was under the ownership of Invensys plc in the late 1990s, the parent company was dropping not-so-subtle hints that the industrial gearbox manufacturer was not part of its long-term plans. Yet Hansen’s CEO Ivan Brems never dreamed that, less than a decade later, he would be working for an Indian company.

When we have problems with gearset failure, a common diagnosis is misalignment. What exactly is that and how do we prevent it?
The second most common "killer" of good gear sets is misalignment (dirt, or abrasive wear, is first). Gear teeth simply won't carry the load if they don't touch, and the portion that does touch has to carry an overload to make up for the missing contact area.

The quality of a gear and its performance is determined by the following five parameters, which should be specified for each gear: Pitch diameter, involute form, lead accuracy, spacing accuracy, and true axis of rotation. The first four parameters can be measured or charted and have to be within tolerance with respect to the fifth. Pitch diameter, involute, lead, and spacing of a gear can have master gear quality when measured or charted on a testing machine, but the gear might perform badly if the true axis of rotation after installation is no longer the same one used when testing the gear.

The dimensions of the worm and worm gear tooth surfaces and some of the worm gear drive parameters must be limited in order to avoid gear undercutting and the appearance of the envelope of lines of contact on the worm surface. The author proposes a method for the solution of this problem. The relations between the developed concept and Wildhaber's concept of the limit contact normal are investigated. The results of computations are illustrated with computer graphics.

In May of this year the U.S. International Trade Commission made public its Report to the President on the condition of the U.S. gear industry. This 200+ page document is the result of a two-year study by the commission, with the help of the AGMA staff and members. It is the most comprehensive and current analytical coverage of the industry conditions and tends presently available. Because of the importance of this report to the industry, GEAR TECHNOLOGY is devoting a good portion of this issue to reprinting the Executive Summary for our readers.

In many gear transmissions, a tooth load on one flank is significantly higher and is applied for longer periods of time than for the opposite one; an asymmetric tooth shape reflects
this functional difference. This paper describes an approach that rationalizes the degree of asymmetry (or asymmetry factor K) selection to meet a variety of operating conditions and requirements for custom gear drives.

Pitting and micropitting resistance of case-carburized gears depends on lubricants and lubrication conditions. Pitting is a form of fatigue damage. On this account a short time test was developed. The test procedure is described. The "pitting test" was developed as a short time test to examine the influence of lubricants on micropitting. Test results showing the influence of case-carburized gears on pitting and micropitting are presented.

This paper will present data from both laboratory and field testing demonstrating that superfinished components exhibit lower friction, operating temperature, wear and/
or higher horsepower, all of which translate directly into increased fuel economy.

Our research group has been engaged in the study of gear noise for some nine years and has succeeded in cutting the noise from an average level to some 81-83 dB to 76-78 dB by both experimental and theoretical research. Experimental research centered on the investigation into the relation between the gear error and noise. Theoretical research centered on the geometry and kinematics of the meshing process of gears with geometric error. A phenomenon called "out-of-bound meshing of gears" was discovered and mathematically proven, and an in-depth analysis of the change-over process from the meshing of one pair of teeth to the next is followed, which leads to the conclusion we are using to solve the gear noise problem. The authors also suggest some optimized profiles to ensure silent transmission, and a new definition of profile error is suggested.

The paper describes a procedure for the design of internal gear pairs, which is a generalized form of the long and short addendum system. The procedure includes checks for interference, tip interference, undercutting, tip interference during cutting, and rubbing during cutting.

Solutions to the governing equations of a spur gear transmission model, developed in a previous article are presented. Factors affecting the dynamic load are identified. It is found that the dynamic load increases with operating speed up to a system natural frequency. At operating speeds beyond the natural frequency the dynamic load decreases dramatically. Also, it is found that the transmitted load and shaft inertia have little effect upon the total dynamic load. Damping and friction decrease the dynamic load. Finally, tooth stiffness has a significant effect upon dynamic loadings the higher the stiffness, the lower the dynamic loading. Also, the higher the stiffness, the higher the rotating speed required for peak dynamic response.

An accurate and fast calculation method is developed to determine the value of a trigonometric function if the value of another trigonometric function is given. Some examples of conversion procedures for well-known functions in gear geometry are presented, with data for accuracy and computing time. For the development of such procedures the complete text of a computer program is included.

As is well known in involute gearing, “perfect” involute gears never work perfectly in the real world.
Flank modifications are often made to overcome the influences of errors coming from manufacturing and assembly processes as well as deflections of the system. The same discipline applies to hypoid gears.

One of the hot items on the public agenda these days is "The Environment." Suddenly everyone wants to save the whales and the rain forest. Politicians, rock stars, and big business have all discovered that you can't get anything but good press for saying that you're in favor of trees and marine mammals.

Now that the new tax bill has been passed, the time has come to begin evaluating how it will affect investment strategies in the machine tool business. Your first reaction may be to think that any motivation to invest in capital improvements in your company is gone, because both the investment tax credit and the accelerated depreciation on capital investment have been removed from the tax law. After all, if Uncle Sam is not going to help us out through some short term tax gains, why should we bother? Can we afford to bother?

"We have met the enemy and he is us," says Pogo, the cartoon character. The enemy is the crisis in our educational system, and "crisis" is the only term that accurately describes the situation. It is every bit as serious, if not more so, than the crisis that followed the Soviet launching of Sputnik in 1957 - and for many of the same reasons. Our failing public education system threatens our position int he global political and business arenas; and this time, it's not just the Soviets or the Japanese who need to be taken seriously as competitors. Every country int he world that graduates better prepared students than we do - and there are a great many of them - has us at a competitive disadvantage.

In this study, the combined influence of shaft misalignments and gear lead crown on load distribution and tooth bending stresses is investigated. Upon conclusion, the experimental results are correlated with predictions of a gear load distribution model, and recommendations are provided for optimal lead crown in a given misalignment condition.

As the international business community grows closer together, the
need for understanding differences between national and international
gear rating standards becomes increasingly important for U.S. gear
manufacturers competing in the world market.

The manufacturing process to produce a gear essentially consist of: material selection, blank preshaping, tooth shaping, heat treatment, and final shaping. Only by carefully integrating of the various operations into a complete manufacturing system can an optimum gear be obtained. The final application of the gear will determine what strength characteristics will be required which subsequently determine the material and heat treatments.

In robot configurations it is desirable to be able to obtain an arbitrary orientation of the output element or end-effector. This implies a minimum of two independent rotations about two (generally perpendicular) intersecting axes. If, in addition, the out element performs a mechanical task such as in manufacturing or assembly (e.g., drilling, turning, boring, etc.) it may be necessary for the end-effector to rotate about its axis. If such a motion is to be realized with gearing, this necessitates a three-degree-of-freedom, three-dimensional gear train, which provides a mechanical drive of gyroscopic complexity; i.e., a drive with independently controlled inputs about three axes corresponding to azimuth, nutation, and spin.

This paper addresses Austempered Ductile Iron (ADI) as an emerging Itechnology and defines its challenge by describing the state-of-the-art of incumbent materials. The writing is more philosophical in nature than technical and is presented to
establish a perspective.

In the past, the coffee breaks and
dinner events at Sigma Pool’s gear
seminars have often triggered future
process development and product
improvements. This was still the case
during the 2009 installment where
customers and suppliers talked shop
inside and outside the banquet hall on the new market and technology challenges currently facing the gear industry.

"It's show time!" Ready or not, on Sept 3, the biennial International Machine Tool Show opens at McCormick Place, Chicago. Planning a show that encompasses displays from over 1000 companies from 29 nations and an associated technical conference presenting more than 200 papers on 50 topics has not been without its problems.

The most conclusive test of bevel and hypoid gears is their operation under normal running conditions in their final mountings. Testing not only maintains quality and uniformity during manufacture, but also determines if the gears will be satisfactory for their intended applications.

Until recently, form gear grinding was conducted almost exclusively with dressable, conventional abrasive grinding wheels. In recent years, preformed, plated Cubic Boron Nitride (CBN) wheels have been introduced to this operation and a considerable amount of literature has been published that claim that conventional grinding
wheels will be completely replaced in the future. The superior machining properties of the CBN wheel are not disputed in this paper.

Worm gearing is of great antiquity, going back about 2100 years to Archimedes, who is generally acknowledged as its inventor.
Archimedes' concept used an Archimedial spiral to rotate a toothed wheel. Development of the worm gearing principle progressed along conventional lines until about 500 years ago when Leonardo DaVinci evolved the double enveloping gear concept.

These are changing times for industry. Trauma and uncertainty are always a part of change, and change is not always for the better. Change is usually forced, most frequently by competition. Our competitive free enterprise system should be able to respond to competition because that's its basis. These are critical years. If we do not respond effectively to change and competition, it could be disasterous.

History comes around full circle. It is interesting to talk to gear manufacturers who service the defense, aerospace, automotive and computer industries and find that their sales, production and backlogs reflect excellent and, in some cases, record breaking business.

Anyone involved in the design, manufacture and use of gears is concerned with three general characteristics relative to their application: noise, accuracy, and strength or surface durability. In the article, we will be dealing with probably the most aggravating of the group, gear noise.

Before we get into projections and prognostications about the future, let’s take a minute to review 2012. For many in the gear industry, the year was better than expected. Some manufacturers
had a very successful year leading up to an even more successful manufacturing trade show (IMTS 2012). Others were searching for more business, hoping that the general
state of the economy wouldn’t make things worse. In some cases, it did.

In the process of developing gear trains, it occasionally occurs that the tip of one gear will drag in the fillet of the mating gear. The first reaction may be to assume that the outside diameter of the gear is too large. This article is intended to show that although the gear dimensions follow AGMA guidelines, if the gear is cut with a shaper, the cutting process may not provide sufficient relief in the fillet area and be the cause of the interference.

When they’re not solving the latest
mechanical engineering puzzle, the
seven members of the group sINGer are
busy engineering their voices to create
the perfect sound. Yes, you read that correctly. Mechanical engineers do have hobbies outside of gears.

Much of the existing guidelines for making large, high-performance gears for wind turbine gearboxes exhibit a need for improvement. Consider: the large grinding stock used to compensate for heat treatment distortion can significantly reduce manufacturing productivity; and, materials and manufacturing processes are two other promising avenues to improvement. The work presented here investigates quenchable alloy steels that, combined with specifically developed Case-hardening and heat treatment processes, exhibits reduced distortion and, in turn, requires a smaller grinding stock.

This article discusses briefly some common manufacturing problems relating to coarse pitch gears and their suggested solutions. Most of the discussion will be limited to a low-quality production environment using universal machine tools.

The past several months have been filled
with uncertainty. Everyone wanted to wait and see who would be our next president and how the political landscape might change. Now the elections are over, and the polls are all closed, so we should all be getting back to business, right? Publisher Michael Goldstein shares insight from our state-of-the-gear-industry survey.

Major sponsorship of an Indy car was working out well for racing fans Mike Chaplin and John Storm. On May 25, a warm, clear day, the co-founders of Contour Hardening watched from their racetrack suite as their car, a bullet on wheels, tore into sixth place at the Indy 500.

IMTS is back in town, From Sept. 7 through Sept. 15, the largest industrial exhibition in the Western Hemisphere will fill one of the largest exhibition centers in the world. A show of this magnitude is a little like the 500 lb. gorilla in your dining room - hard to ignore.

Gearing for Munchkins
Gene Kasten, president of Repair Parts, Inc., of Rockford, IL, is the proud owner of a miniature Barber-Colman hobber, the only one of its kind in the world. The machine, a replica of the old B-C "A" machine, was built between 1933 and 1941 by W. W. Dickover, who devoted 2, 640 hours of his spare time to the project.

Today motion control systems are migrating from analog to digital technology at an ever increasing rate because digital technology at an ever-increasing rate because digital drives provide performance equal to or exceeding that of analog drives, plus information to run your machine more effectively and manage your quality program and your business. Most of this data is simply not available from analog drives.

Market needs push in 2013, but will it get one? The construction/off-highway
industries have been here before. New equipment, technologies and innovations during an economic standstill that some have been dealing with since 2007.

Most Navy brass would say that Commander D. Michael Abrashoff ran a loose ship. But his style of empowering his crew by delegating authority is changing the way the Navy thinks about management. His speech at the recent annual meeting of the American Gear Manufacturers Association offered a simple, common-sense approach that can be applied not only to running a ship, but also to gear manufacturing or any other industry.

Bearings ain't beanbag. They are complicated. They are big-business. They are often counterfeited. They are used in virtually anything that moves.
But it is the "complicated" part that
challenges OEMs, job shops and other
operations, and, most of all, their
employees. Add to that the countless
other entities around the world that are
intimately involved with bearings and
you can arrive at a semblance of an idea
of just how important these precious
orbs can be to a successful operation.

A universal gear is one generated by a common rack on a cylindrical, conical, or planar surface, and whose teeth can be oriented parallel or skewed, centered, or offset, with respect to its axes. Mating gear axes can be parallel or crossed, non-intersecting or intersecting, skewed or parallel, and can have any angular orientation (See Fig.1) The taper gear is a universal gear. It provides unique geometric properties and a range of applications unmatched by any other motion transmission element. (See Fig.2) The taper gear can be produced by any rack-type tool generator or hobbing machine which has a means of tilting the cutter or work axis and/or coordinating simultaneous traverse and infeed motions.

Question: We just received permission to purchase our first CNC gear inspection system. With capital approvals so hard to come by, especially for inspection equipment, I want to be sure to purchase a system I can count of for years to come. My past experience with purchasing CNC equipment has shown me that serviceability of the computer and the CNC controller portion of the system can be a problem in just a few years because of the obsolescence factor. What information do I need to look for when selecting a supplier to reduce the risk of obsolescence, as well as to reduce the long-term servicing costs in the computer and controls portion of the system?

In Part I differences in pitting ratings between AGMA 218, the draft ISO standard 6336, and BS 436:1986 were examined. In this part bending strength ratings are compared. All the standards base the bending strength on the Lewis equation; the ratings differ in the use and number of modification factors. A comprehensive design survey is carried out to examine practical differences between the rating methods presented in the standards, and the results are shown in graphical form.

Three years ago, coated gears seemed to be the perfect solution for the Micro Marine Corporation. The early designs for the gear drive of their MicroCAT human-powered boat used a combination of thin-film dry gear coatings with lubrication and wear-resistance properties. These coatings simplified their design, provided corrosion resistance, made the gear drive environmentally safe and eliminated the need for gear drive lubrication and maintenance. It was a success story in the making.

Ready or not, QS-9000 is here. If you are a first-tier supplier to one of the Big Three automotive companies, you've already heard that compliance with this new quality standard is now an entry-level requirement for doing business with Ford, General Motors and Chrysler. If you're a second-or third-tier supplier, you can expect the ripple effect of this new standard to hit your company one way or another.

The Forest City Gear booth at Gear Expo featured a wide variety of gears utilized in medical equipment, Indy cars, fishing reels, even the recently launched Mars Rover. Scattered among Forest City’s products in Cincinnati were some unique gear sculptures created by an artist that finds more inspiration from the pages of industrial magazines than art galleries.

A very important parameter when designing a gear pair is the maximum surface contact stress that exists between two gear teeth in mesh, as it affects surface fatigue (namely, pitting and wear) along with gear mesh losses. A lot of attention has been targeted to the determination of the maximum contact stress between gear teeth in mesh, resulting in many "different" formulas. Moreover, each of those formulas is applicable to a particular class of gears (e.g., hypoid, worm, spiroid, spiral bevel, or cylindrical - spur and helical). More recently, FEM (the finite element method) has been introduced to evaluate the contact stress between gear teeth. Presented below is a single methodology for evaluating the maximum contact stress that exists between gear teeth in mesh. The approach is independent of the gear tooth geometry (involute or cycloid) and valid for any gear type (i.e., hypoid, worm, spiroid, bevel and cylindrical).

Knowing the right thing to do isn't hard. Most often, it's very obvious. Actually doing it is something else again. For example, we all know that we probably eat too much refined sugar and fat, but when the double chocolate cheesecake come by, it's easy to convince ourselves that one piece won't hurt.

Involute spur gears are very sensitive to gear misalignment. Misalignment will cause the shift of the bearing contact toward the edge of the gear tooth surfaces and transmission errors that increase gear noise. Many efforts have been made to improve the bearing contact of misaligned spur gears by crowning the pinion tooth surface. Wildhaber(1) had proposed various methods of crowning that can be achieved in the process of gear generation. Maag engineers have used crowning for making longitudinal corrections (Fig. 1a); modifying involute tooth profile uniformly across the face width (Fig. 1b); combining these two functions in Fig. 1c and performing topological modification (Fig. 1d) that can provide any deviation of the crowned tooth surface from a regular involute surface. (2)

Universal machines capable of cutting both spur and helical gears were developed in 1910, followed later by machines capable of cutting double helical gears with continuous teeth. Following the initial success, the machines were further developed both in England and France under the name Sunderland, and later in Switzerland under the name Maag.

Cost cutting. It's the aerobics of the 90s for businesses large and small. More than just the latest buzzword or 90-second flash-in-the-panacea, it's a survival technique. Companies that aren't trimming the fat now may not be around in five years to regret that they didn't.

It's not easy being big. Maybe that's not exactly how the phrase goes, but it's applicable, particularly when discussing the quality requirements of large gears. The size alone promises unique engineering challenges. BONUS Online Exclusive: Big or Small - Inspection is Key to Success.

Product announcements so often trumpet minor, incremental advances with works like "revolutionary" and "unique" that even the best thesaurus can fail to offer a fresh alternative to alert the reader when something really innovative and important is introduced. In the case of Mitsubishi's new CNC gear shaper, the ST25CNC, both terms apply.

Much information has been written on gear inspection, analytical. functional. semiautomatic and automatic. In most
cases, the charts, (if you are lucky enough to have recording
equipment) have been explained.

Machine tool companies are expanding capabilities to better accommodate the changing face of manufacturing. Customers want smaller-sized equipment to take up less valuable floor space, multifunctional machines that can handle a variety of operations and easy set-up changes that offer simplified operation and maintenance.

Many people seem to be counting this year's Gear Expo in Nashville as a resounding success. There were 180 American and international exhibitors occupying over 50,000 square feet of exhibit space in the Nashville Convention Center, with total attendance of 2,700. This figure is dramatically down from past shows but that doesn't seem to be an issue with the show organizers. According to Kurt Medert, vice president of AGMA;s Administrative Division, even though attendance was off from the 1997 show, the exhibitors were pleased with the quality of the people who did come to the show. "This was an excellent show for us," said Marty Woodhouse, vice president of sales for Star Cutter Company and chairman of AGMA's Gear Expo committee. "Our customer base was there and they came to buy. It was very active."

A common design goal for gears in helicopter or turboprop power transmission is reduced weight. To help meet this goal, some gear designs use thin rims. Rims that are too thin, however, may lead to bending fatigue problems and cracks. The most common methods of gear design and analysis are based on standards published by the American Gear Manufacturers Association. Included in the standards are rating formulas for gear tooth bending to prevent crack initiation (Ref. 1). These standards can include the effect of rim thickness on tooth bending fatigue (Ref 2.). The standards, however, do not indicate the crack propagation path or the remaining life once a crack has started. Fracture mechanics has developed into a useful discipline for predicting strength and life of cracked structures.

Gear Expo 99, AGMA's biennial showcase for the gear industry, has left the Rust Belt this year and landed in Music City U.S.A., Nashville, Tennessee. The event, with exhibitors from around the globe showing off the latest in gear manufacturing as well as metal working processes, will be held at the Nashville Convention Center, October 24-27, 1999. According to Kurt Medert, AGMA vice president and Gear Expo show manager, "In choosing Nashville, AGMA;s Trade Show Advisory Council found a city that is an excellent trade show site. It has the right mix of convention center, nearby hotels, and a clean downtown area with entertainment readily available for the exhibitors and visitors alike. Nashville is in the heart of southern industry, which we see as a focus of growth for the gear industry and its customers."

AGMA has started to replace its 2000-A88 standard for gear accuracy with a new series of documents based largely on ISO standards. The first of the replacement AGMA standards have been published with the remainder coming in about a year. After serving as a default accuracy specification for U.S. commerce in gear products for several decades, the material in AGMA 2000-A88 is now considered outdated and in need of comprehensive revision.

New freedom of motion available with CNC generators make possible improving tooth contact on bevel and hypoid gears. Mechanical machines by their nature are inflexible and require a special mechanism for every desired motion. These mechanisms are generally exotic and expensive. As a result, it was not until the introduction of CNC generators that engineers started exploring motion possibilities and their effect on tooth contact.

Methods of examining large ring gear
teeth to detect surface breaking discontinuities have often been time-consuming and limited in terms of data collected. Methods such as visual and magnetic particle inspection can miss critical discontinuities. However, a new ASTM international standard provides a more effective method for gear examination using eddy current array, a technology that has been widely used but, until now, not standardized.

The auction has been held. The warehouse is bare. The computers
and furniture are being packed, and Cadillac Machinery, the company
started by my father in 1950, and of which I was president for more
than 25 years, is close to being no more.

What Is Whisker-Reinforced Ceramic?
Whisker-reinforced ceramic as applied to cutting tool inserts comprises a matrix of aluminum oxide into which approximately 50% by volume of high-purity silicon carbide "whiskers" are randomly dispersed. The "whiskers" are, in fact, single crystals having dimensions of approximately 0.6 microns in diameter x 10-80 microns in length. These "whiskers" have a tensile strength on the order of 1,000,000 psi (690 MPa). The composite material that is the best known and most widely applied using this technology is designated WG-300 and manufactured by the Greenleaf Corporation of Saegertown, PA.

What can be done about the rising cost of labor? Mr. Robert Reich, U.S. Secretary of Labor, has already indicated the administration's intention of pushing the minimum wage from $4.25 to $4.50 per hour and indexing it for inflation. That means that every jiggle in the inflation chart will push the minimum wage higher.

Imagine the $10 bill with the face of Edwin R. Fellows on it and on the back, a picture of his invention: the gear shaping machine. Or the $5 bill with George B. Grant and a picture of the first hobbing machine, which he built.

There are varying opinions as to what constitutes innovation, but in our industry and in the engineering world as a whole, we typically think of innovation as being the use of technologies different from those we use at the moment to do things better, faster and cheaper.

The organizers of Gear Expo 2007 promise to combine the most popular features of shows past with some innovations for this year’s attendees. By the time the show closes on October 10, the association hopes its targeted 175 exhibitors walk away with new insights leading to profitability and renewed contacts.

A few years ago, during a presidential election campaign, I saw an editorial cartoon that depicted a man standing outside a voting booth with a bemused expression on his face. Over the door to the booth was a quotation from Dante: "Abandon hope, all ye who enter here." Unfortunately for all of us, the grim jest is just as timely now. Once again, when we make our choice for president this year, the pick seems to be between Mr. Well-He's-Not-Actually-Awful and Mr. At-Least-He's-Not-The-Other-Guy. A candidate who can arouse truly positive and hopeful feelings in the electorate is once again not on the ballot.

Industrial gear standards have been used to support reliability through the specification of requirements for
design, manufacturing and verification.
The consensus development of an
international wind turbine gearbox
standard is an example where gear
products can be used in reliable
mechanical systems today. This has
been achieved through progressive
changes in gear technology, gear
design methods and the continual
development and refinement of gearbox
standards.

AGMA's Gear Expo '89, "The Cutting Edge," opens at the David Lawrence Convention Center in Pittsburgh, PA, on Nov. 6 and runs through Nov. 8. This year's show is "the largest trade show ever conceived specifically for the gear industry," according to Rick Norment, AGMA's executive director. The show is 60% larger in terms of floor space than the 1987 show, and over 90%of the booths have been sold.

The name Gleason is practically synonymous with gear manufacturing. Since the company was founded in 1865, the technology of gear manufacturing has
been its focus, its core and its competitive advantage.

AGMA's Gear Expo '93 is expected to be at least 10% larger in terms of floor space than the '91 show, according to Joe Franklin, AGMA's executive director. "As of June 1, we have 80 exhibitors registered", he says.

Forty of Gear Technology's pre-show and show issue advertisers will be exhibiting a wide range of goods and services at AGMA's Gear Expo '93. The exhibition will be held October 10-13 at Cobo Conference & Exhibition Center in Detroit, MI. Below is an alphabetical listing of these advertisers and a preview of what can be seen at their booths.

So there is little chance that they need the same software to assist with their work. Gone are the days when companies wrote their own code and process engineers thumbed the same tattered reference book.

Companies around the world are learning to embrace the environment, and the gear industry is no exception. This special section takes a look at how some gear manufacturers are doing
their part to conserve resources, preserve and protect the environment, and give back to the land. What we’ve found is that adopting environmental
measures is far more than just good
corporate citizenship. For many gear industry companies, good environmental practices also turn out to be good for the bottom line.

Although a comprehensive on-site gearbox inspection is desirable in many situations, there may be constraints that limit the extent of the inspection such as cost, time, accessibility and
qualified personnel. This article describes the equipment and techniques necessary to perform an on-site gearbox inspection.

Compact, custom and portable solutions
are gaining more attention in manufacturing today as companies seek out
the tools that offer the greatest productivity gains on the shop floor. Gear
inspection seems to be following suit.

Sentences that start off with
some variance of “I don’t want
to brag, but…” are generally a
good indicator that it’s precisely
what the speaker intends to
do and typically end with bold
proclamations that are immediately
and eminently quotable — the kind of quotes perfect for beginning a feature
story with an eye-catching artistic flourish.

The gear industry is full of storytellers. It's a niche market that boasts a remarkable cast of characters that have been sharing their stories with us for 30 years. In that time, the editors and staff of Gear Technology magazine have had the privilege to report the ins and outs of this highly-specialized industry. From technical articles to case studies and features, the main focus of this magazine has been to "provide a forum of discovery and innovation for you, the gear manufacturing industry." Our Publisher, Michael Goldstein, said as much in our inaugural issue of May/June 1984.

Material losses and long production times are two areas of conventional spur and helical gear manufacturing in which improvements can be made. Metalforming processes have been considered for manufacturing spur and helical gears, but these are costly due to the development times necessary for each new part design. Through a project funded by the U.S. Army Tank - Automotive Command, Battelle's Columbus
Division has developed a technique for designing spur and helical gear forging and extrusion dies using computer aided
techniques.

Step right up! Get your U.S. government gravy here! We’re the U.S. Treasury Department’s Troubled Asset Relief Program, and we’re printing money like we’re—well—the U.S. reasury. If you’ve got trouble, then get your assets in line!

This article describes a new technique for the size determination of external Involute splines by using a span measuring method. It provides application performance information
demonstrating how this method and its
measurements correlate with the traditional spline ring gage sizing method.

The world economy is in turmoil.
A year ago, the Dow Jones industrial
average was more than 14,000. As
I write this, after eight straight days
of massive losses and a week of wild
up-and-down swings, the average
sits at about 8,900.

There is an increasing significance of screw helical and worm gears that combine use of steel and plastics. This is shown by diverse and continuously rising use in the automotive and household appliance
industries. The increasing requirements for such gears can be
explained by the advantageous qualities of such a material combination in comparison with that of the traditional steel/bronze pairing.

Over the past few months I've talked with several different gear manufacturers who are in the process
of upgrading their gear making equipment
with modern CNC machine tools. Each of these manufacturers has come to the realization that in order to stay competitive, he needs to streamline operations and become more
efficient...

In one of my many visits to northern New York state, which included the St. Lawrence River (Thousand Islands Region) and the Adirondack Mountains, I visited Croghan, a village on the Beaver River, which is fed by the Stillwater Resevoir in the Adirondack Mountains. At the base of a dam within the village, I found the remnants of a water turbine and a bevel gear drive system. Having worked for The Gleason Works for many years, I was intrigued by the remains of the bevel gears, which appeared to have had wooden teeth at one time.

In today’s globalized manufacturing, all industrial products having dimensional constraints must undergo conformity specifications assessments on a regular basis. Consequently, (standardization) associated with GD&T (geometrical dimensioning and tolerancing) should be un-ambiguous and based on common, accepted rules. Of course gears - and their mechanical assemblies - are special items, widely present in industrial applications where
energy conversion and power transmission are involved.

If you are like most navigators of the printed page, the first thing you read in this final 2013 issue of Gear Technology was our State of the Gear
Industry Survey. And who would blame you? It’s not Sabermetrics, but once you’ve read it you’ll have a pretty
clear snapshot of last year and a peek
into the next. But if you also like to get a little closer to the bone about things, what follows are the collected opinions of five well-regarded people in the gear industry speaking to a number of issues with relevance.

The major focus of the American Gear Manufacturers Association standards activity has been the accurate determination of a gearbox's ability to transmit a specified amount of power for a given amount of time. The need for a "level playing field" in the critical arena was one of the reasons the association was formed in the first place. Over the past 85 years, AGMA committees have spent countless hours "discussing" the best ways to calculate the rating of a gear set, often arguing vigorously over factors that varied the resulting answers by fractions of a percentage point. While all that "science" was being debated in test labs and conference rooms all over the country, out industry's customers were conducting their own experiments through the daily operation of gear-driven equipment of all types.

AGMA's Gear Expo '91, "The World of Gearing," opens October 20 and runs through October 23 at the Cobo Conference & Exhibition Center in "The Heart of the Manufacturing Industry," Detroit, MI. Gear Expo '91 is "the largest trade show ever specifically organized for the gear industry," according to Rich Norment, AGMA's Executive Director.

High demands for cost-effectiveness and improved product quality can be achieved via a new low pressure
carburizing process with high pressure gas quenching. Up to 50% of the heat treatment time can be saved. Furthermore, the distortion of the gear parts could be reduced because of gas quenching, and grinding costs could be saved. This article gives an overview of the principles of the process technology and the required furnace technology. Also, some examples of practical applications
are presented.

Gear Technology’s annual State-of-
the-Gear-Industry survey polls gear manufacturers about the latest trends and opinions relating to the overall health of the gear industry. As in years
past, the survey was conducted anonymously, with invitations sent by e-mail to gear manufacturing companies
around the world.

When gears are case-hardened, it is known that some growth and redistribution of stresses that result in geometric distortion will occur. Aerospace gears require post case-hardening grinding of the gear teeth to achieve necessary accuracy. Tempering of the case-hardened surface, commonly known as grinding burn, occurs in the manufacturing
process when control of the heat generation at the surface is lost.

The NASA Lewis Research Center investigated the effect of tooth profile on the acoustic behavior of spur gears through experimental techniques. The tests were conducted by Cleveland State University (CSU) in NASA Lewis' spur gear testing apparatus. Acoustic intensity (AI) measurements of the apparatus were obtained using a Robotic Acoustic Intensity Measurement System (RAIMS). This system was developed by CSU for NASA to evaluate the usefulness of a highly automated acoustic intensity measurement tool in the reverberant environment of gear transmission test cells.

The first part of this article, which ran in the September/October 1994 issue, explained the fundamentals of gear hobbing and some of the latest techniques, including methods of hob performance analysis and new tool configurations, being used to solve specific application problems. In this issue, the author continues his exploration of hobbing by describing the effects of progress on requirements in accuracy, as well as the latest in materials, coating and dry hobbing.

For environmental and economic reasons, the use of coolant in machining processes is increasingly being questioned. Rising coolant prices and disposal costs, as well as strains on workers and the environment, have fueled the debate. The use of coolant has given rise to a highly technical system for handling coolant in the machine (cooling, filtering) and protecting the environment (filter, oil-mist collector). In this area the latest cutting materials - used with or without coolant - have great potential for making the metal-removal process more economical. The natural progression to completely dry machining has decisive advantages for hobbing.

Transmission of power between nonparallel shafts is inherently more difficult than transmission between parallel shafts, but is justified when it saves space and results in more compact, more balanced designs. Where axial space is limited compared to radial space, angular drives are preferred despite their higher initial cost. For this reason, angular gear motors and worm gear drives are used extensively in preference to parallel shaft drives, particularly where couplings, brakes, and adjustable mountings add to the axial space problem of parallel shaft speed reducers.

NC and CNC machines are at the heart of manufacturing today. They are the state-of-the-art equipment everybody has (or is soon going to get) that promise to lower costs, increase production and turn manufacturers into competitive powerhouses. Like many other high tech devices (such as microwaves and VCRs), lots of people have and use them - even successfully - without really knowing much about how they operate. But upgrading to CNC costs a lot of money, so it's crucial to separate the hype from the reality.

It's every gear manufacturer's nightmare. Your company had been named as a defendant in a product liability suit - one involving serious injuries and death. You're facing endless court appearances, monumental legal fees, and, possibly, seven figure settlements our of your coffers. The very existence of your business could be on the line. The question is, how do you prevent this nightmare from becoming a painful reality.

Below are listed a variety of commonly used constants arranged numerically to permit ease of reference. Wherever an asterisk (*) is shown, the constant is exact as given, it being generally a mathematical constant or one fixed by definition. In cases where the first constant listed is followed by another in parenthesis, the first is the round number generally used, while the second is the more exact value.

Quality gear inspection means doing the "right" inspections "right." A lot of time and money can be spent doing the wrong types of inspections related to function and doing them incorrectly. As we will discover later, such things as runout can creep into the manufacturing and inspection process and completely ruin any piece of data that is taken. this is one of the most important problems to control for quality inspection.

Question: In the January/February issue of your magazine, we came across the term "electronic gearbox." We have seen this term used elsewhere as well. We understand that this EGB eliminates the change gear in the transmission line, but not how exactly this is done. Could you explain in more detail?

There is one dimension common to both members of a pair of properly mating spur gears - the base pitch (BP). This base pitch is equal to the circular pitch of the gear on the base circle (see Fig. 1). For a helical gear, the base pitch can be described in either the transverse or normal plane, and is called the transverse base pitch (TBP) or normal base pitch (NBP), respectively. For parallel axis helical gears, both the TBP and NBP must be the same on both mating gears. For skew axis helical gears, only the NBP must be common.

Taxes may be one of the only two sure things in life, but that doesn't make them popular. Nobody is happy to pay them, and the bigger the amount due, the unhappier the taxpayer. Conversely, politicians know that coming out in favor of a tax cut is the equivalent of voting for apple pie and motherhood. It's a sure-fire success at the ballot box.

Gear manufacturing schedules that provide both quality and economy are dependent on efficient quality control
techniques with reliable measuring equipment. Given the multitude of possible gear deviations, which can be found only by systematic and detailed measuring of the gear teeth, adequate quality control systems are needed. This is especially true for large gears, on which remachining or rejected
workpieces create very high costs. First, observation of the gears allows adjustment of the settings on the equipment right at the beginning of the process and helps to avoid unproductive
working cycles. Second, the knowledge of deviations produced on the workpiece helps disclose chance inadequacies on the production side: e.g., faults in the machines and tools used, and provides an opportunity to remedy them.

Prior to the introduction of titanium nitride to the cutting tool industry in the early 1980s, there was very little progress in the general application of hobbing in the gear cutting industry. The productivity gains realized with this new type of coating initiated a very active time of advancement in the gear manufacturing process.

Today it is common practice when
climb hobbing to keep the direction of
the hob thread the same as that of the
helical gear. The same generalization
holds true for the mass production of
gears for automobiles. It is the authors' opinion, however, that conventional hobbing with a reverse-handed hob is more effective for the high-speed manufacture of comparatively small module gears for automobiles. The authors have proven both experimentally and theoretically that reverse-handed conventional hobbing, using a multi-thread hob with a smaller diameter is very effective for lengthening the life of the hob and for increasing cutting efficiency at high speeds.

Question: We are interested in purchasing our first gear hobbing machine. What questions should we ask the manufacturer, and what do we need to know in order to correctly specify the CNC hardware and software system requirements?

Over the past several months, many gear manufacturers and industry suppliers have been telling me how busy they
are. Their backlogs are the largest in history, their sales the highest they’ve been in many years. They’ve invested in new capabilities, new machinery and people.

Bringing new or improved products to
market sooner has long been proven profitable for companies. One way to help shorten the time-to-market is to accelerate validation testing. That is, shorten the test time required to validate a new or improved product.

Over the years, we have traveled extensively throughout the industrialized world, and became increasingly aware of the availability of enormous amounts of technical writing
concerning research, experiments, and
techniques in the gear manufacturing field. New manufacturing methods, materials, and machines were continuously being developed, but the technical information about them was
not readily available to those that could best use it. There was no central source for disseminating this knowledge.

The Internet. Big deal. Now that you've dialed up weird politics.com, http://www.Elvis sightings and alt.naughty bits, what's online that's useful? Anything that would make your job easier, answer important questions, solve tough design problems? Information about, say, gearing? Is there anything out there in cyberspace worth the expense and hassle of going after?

Plastic gears are serious alternatives to traditional metal gears in a wide variety of applications. The use of plastic gears has expanded from low-power, precision motion transmission into more demanding power transmission applications. As designers push the limits of acceptable plastic gear applications, more is learned about the behavior of plastics in gearing and how to take advantage of their unique characteristics.

A good many things bother me about election years - the annoying sound bites, the negative commercials, the endless political over-analysis. But what bothers me most about the coming election is this: So far (when I'm writing this, it's admittedly early in the campaign) there's little or no talk about what is one of the most critical national issues of the next thirty years - our growing government debt.

Presumably, everyone who would be interested in this subject is already somewhat familiar with testing of gears by traditional means. Three types of gear inspection are in common use: 1) measurement of gear elements and relationships, 2) tooth contact pattern checks and 3) rolling composite checks. Single Flank testing falls into this last category, as does the more familiar Double Flank test.

Gear grinding is one of the most expensive and least understood aspects of gear manufacturing. But with pressures for reduced noise, higher quality and greater efficiency, gear grinding appears to be on the rise.

Today gear drive operations have several options when selecting the proper lubricant for their gearboxes. As in the past, the primary lubricant used for gearbox lubrication is mineral oil. But with the advances in technology, synthetic hydrocarbons (PAOs) and polyglycols show very specific advantages in certain applications. With gear drives becoming more and more precise, it is now also to the benefit of the gear operator to verify that he or she has the proper additive package and viscosity in the lubricant selected. Fig. 1 shoes that a gear oil is a combination of a base oil and specific additives. The base oils can be either mineral oil, a synthetic or even in some cases a combination of the two.

Beginning with this issue, one of the last bits of the "old" Gear Technology is gone. From now on we'll be running the new picture of me you see on this page. It was time, my art and editorial staff explained to me, to move ahead with the rest of the updated art and editorial in the magazine. (I emphatically deny that the real motivation for the new picture was putting a stop to the ever-increasing number of jabs from certain friends about my "Dorian Gray" look.)

In today's economy, when purchasing a new state-of-the-art gear shaper means a significant capital investment, common sense alone dictates that you develop strategies to get the most for your money. One of the best ways to do this is to take advantage of the sophistication of the machine to make it more than just a single-purpose tool.

What was once recognized as the unique
genius of America is now slipping away
from us and, in many areas, is now seen as a "second rate" capability. Unless
action is taken now, this country
is in real danger of being unable to regain its supremacy in technological development and economic vigor. First Americans must understand the serious implications of the problem; and second, we must dedicate ourselves to national and local actions that will ensure a greater scientific and
technological literacy in America.

How well you conduct your inspections can be the difference-maker for securing high-value contracts from your
customers. And as with most other segments of the gear industry,
inspection continues striving to attain “exact science” status. With that thought in mind, following is a look at the state of gear inspection and what rigorous inspection practices deliver—quality.

"Opportunity is the start of great enterprises." said the Greet statesman Demosthenes, and what was true 2300 years ago is no less true now. Plenty of opportunities which can grow into great - and successful - enterprises are waiting for us right now if we only have the foresight to take advantage of them.

A medieval philosopher once said that if he knew for certain the world was to end tomorrow, he would be sure to take time to plant an apple tree in his garden today. The recent events in the world financial capitals have seemed a bit like prior notice of something cataclysmic, but like the philosopher, we can still find some reasons for hope in the face of an uncertain future. The good news for our industry is that four important efforts on the part of various organizations promise to have long-term positive effects on both the gear and machine tool businesses.

Observations while traveling through Hungary last November...this is a very ancient country; people have lived and worked here along the Danube River since early times, and change is just another piece of the landscape. Still, the collapse of the old Communist economy is one of the more remarkable phenomena in a land that has seen and lived under different versions of the "new world order" since the first barbarian invasions. The difference is that this time, the people themselves are working the change, and the results are exciting in their variety and effect.

In a very general sense, increasing the hardness of a steel gear increases the strength of the gear. However, for each process there is a limit to its effectiveness. This article contains background information on each of the processes covered. In each section what is desired and what is achievable is discussed. Typical processes are presented along with comments on variables which affect the result. By reviewing the capabilities and processes, it is possible to determine the limits to each process.

Dear Editor:
Your article on the ITC's Report to the President on the condition of the U.S. gear industry (Sept./Oct. issue) was most interesting. I am wondering if the total report neglected to mention that some of our inability to export gears is due to our reluctance to provide metric countries with the metric module-based gears that overseas customers demand.

The following article is a collection of data intended to give the reader a general overview of information related to a relatively new subject within the gear cutting industry. Although carbide hobbing itself is not necessarily new, some of the methods and types of application are. While the subject content of this article may be quite broad, it should not be considered all-inclusive. The actual results obtained and the speeds, feeds, and tool life used in carbide hobbing applications can vary significantly.

Countless research studies confirm this fact: Companies that advertise aggressively during a recession will flourish after the economic tide turns. Regardless of company size, effective advertising generally requires the services of an agency, and under current economic conditions, you may need one now more than ever. The question is, how do you go about getting the right one for your company.

There are different types of spiral bevel gears, based on the methods of generation of gear-tooth surfaces. A few notable ones are the Gleason's gearing, the Klingelnberg's Palloid System, and the Klingelnberg's and Oerlikon's Cyclo Palliod System. The design of each type of spiral bevel gear depends on the method of generation used. It is based on specified and detailed directions which have been worked out by the mentioned companies. However, there are some general aspects, such as the concepts of pitch cones, generating gear, and conditions of force transmissions that are common for all types of spiral bevel gears.

One of the key questions to be answered when exporting is how you are going to get your product to your customer. All the time, effort, and money you've spent to make a sale in the first place can be wasted if the shipment is late, damaged, or lost, or if delivery becomes an expensive bureaucratic nightmare for either you or the buyer.

Hard Gear Finishing (HGF), a relatively new technology, represents an advance in gear process engineering. The use of Computer Numerical Controlled (CNC) equipment ensures a high precision synchronous relationship between the tool spindle and the work spindle as well as other motions, thereby eliminating the need for gear trains. A hard gear finishing machine eliminates problems encountered in two conventional methods - gear shaving, which cannot completely correct gear errors in gear teeth, and gear rolling, which lacks the ability to remove stock and also drives the workpiece without a geared relationship to the master rolling gear. Such a machine provides greater accuracy, reducing the need for conventional gear crowning, which results in gears of greater face width than necessary.

The Hobbing Process
The hobbing process involves a hob which is threaded with a lead and is rotated in conjunction with the gear blank at a ratio dependent upon the number of teeth to be cut. A single thread hob cutting a 40-tooth gear will make 40 revolutions for each revolution of the gear. The cutting action in hobbing is continuous, and the teeth are formed in one passage of the hob through the blank. See Fig. 1 for a drawing of a typical hob with some common nomenclature.

This is Part II of a two-part series on the basics of gear hobbing. Part I discussed selection of the correct type of hobbing operation, the design features of hobs and hob accuracy. This part will cover sharpening errors and finish hob design considerations.

It is often easy for those outside of the gear industry to get the impression that nothing is changing in our business. After all, all illustrated bimonthly by the covers of this very journal the making of gears has been with us for centuries. However, nothing could be further from the truth.

Runout is a troublemaker! Good shop practice for the manufacture or inspection of gears requires the control of runout.
Runout is a characteristic of gear quality that results in an effective center distance variation. As long as the runout doesn't cause loss of backlash, it won't hurt the function of the gear, which is to transmit smooth motion under load from one shaft to another. However, runout does result in accumulated pitch variation, and this causes non-uniform motion, which does affect the function of the gears. Runout is a radial phenomenon, while accumulated pitch variation is a tangential characteristic that causes transmission error. Gears function tangentially. It is also possible to have a gear with accumulated pitch variation, but little or no runout.

Gear hobbing is a generating process. The term generating refers to the fact that the gear tooth form cut is not the conjugate form of the cutting tool, the hob. During hobbing both the hob and the workpiece rotate in a continuous rotational relationship. During this rotation, the hob is typically fed axially with all the teeth being gradually formed as the tool traverses the work face (see Fig. 1a).

At the next meeting of your association's marketing committee, notice what happens. The rate of taking notes increases dramatically when the market analysis and international trade trends reports begin. Even with the handouts to match the overhead projections of numbers, the audience's pace is furious. This is vital, apparently hard-to-come-by information, and no one wants to miss out. Almost all of the information comes from one source, yet the data offered is only one small dip from an enormous treasure chest - the U.S. Government.

Grinding is a technique of finish-machining, utilizing an abrasive wheel. The rotating abrasive wheel, which id generally of special shape or form, when made to bear against a cylindrical shaped workpiece, under a set of specific geometrical relationships, will produce a precision spur or helical gear. In most instances the workpiece will already have gear teeth cut on it by a primary process, such as hobbing or shaping. There are essentially two techniques for grinding gears: form and generation. The basic principles of these techniques, with their advantages and disadvantages, are presented in this section.

What follows is the first of three articles we will be running on ISO 9000 and what it means for the gear industry. This first article will cover what ISO 9000 is, what some of its benefits - and problems - are, and whether your company should be a candidate for this certification process. In our next issue, we will consider the important question of how, when, and if to hire an ISO 9000 consultant. The final article in this series will discuss ways to save money while streamlining the certification process in your company.

The first part of this article included abrasive wear with two bodies, streaks and scoring, polishing, and hot and cold scuffing. This part will deal with three-body wear, scratches or grooves, and interference wear. Normal, moderate, and excessive wear will be defined, and a descriptive chart will be presented.

The phenomena of deterioration of surfaces are generally very complex and depend on numerous conditions which include the operating conditions, the type of load applied, the relative speeds of surfaces in contact, the temperature, lubrication, surfaces hardness and roughness, and the compatibility and nature of materials.

For the last few years, the market has been tough for the U.S. gear industry. That statement will cause no one any surprise. The debate is about what to do. One sure sign of this is the enormous attention Congress and the federal government are now placing on "competitiveness."

How is it that we woke up one day in the early 1980s to find that apparently American industry was suddenly inefficient, our workforce unproductive and our management inept? Almost overnight industry found its sales dropping dramatically, while for many companies foreign competition became excruciatingly intense. This sudden change in the economic climate proved fatal for many companies and has been nearly as hard on our collective morale. In a country used to winning, we began to hear ourselves talked of as losers.

Organizing a successful trade show exhibit is not unlike running Operation Desert Storm. The logistics can be a nightmare; the expense, horrendous; the details, mind-boggling. About the only thing you won't have to cope with is having someone fire SCUD missiles at you.

The finished gear engineer, the man who is prepared for all emergencies, must first of all know the basic design principles.
Next he must be well versed in all sorts of calculations which come under the heading of "involute trigonometry."

The term "blanking" refers to the initial metal cutting operations in the process planning sequence which produce the contour of a part starting from rough material.
The scope of blanking is:
To remove the excess material
To machine the part to print specifications, except for those surfaces with subsequent finishing operations.
To leave adequate machining stock for finishing operations.
To prepare good quality surfaces for location and clamping of the part throughout the process.

Exporting. It's one of the hot strategies for helping boost businesses of all kinds, gear manufacturing among them. With domestic markets tight and new markets opening up overseas, exporting seems like a reasonable tactic. But while the pressure is on to sell overseas, there is equal, justifiable concern about whether the move is a good one. Horror stories abound about foreign restrictions, bureaucratic snafus, carloads of paperwork, and the complications and nuances of doing business in other languages and with other cultures.

The Shaping Process - A Quick Review of the Working Principle. In the shaping process, cutter and workpiece represent a drive with parallel axes rotating in mesh (generating motion) according to the number of teeth in both cutter and workpiece (Fig. 1), while the cutter reciprocates for the metal removal action (cutting motion).

There are a number of companies
working to change the way broaching is perceived, and over the past 10 years, they’ve incorporated significant
technological changes to make the process more flexible, productive
and accurate.

It has previously been demonstrated that one gear of an interchangeable series will rotate with another gear of the same series with proper tooth action. It is, therefore, evident that a tooth curve driven in unison with a mating blank, will "generate" in the latter the proper tooth curve to mesh with itself.

We are well into an odd-number year, so it must be just about time for another Gear Expo. Indeed, the big show -- Gear Expo 2013 -- kicks off in Indianapolis at 9:00 a.m. Tuesday, September 17, wrapping up Thursday the 19th at 4:00 p.m. And whether you are exhibiting or attending, the bottom line is you are going -- a good thing for you, your company and the tightly knit U.S. gear industry.

Gear shaving is a free-cutting gear finishing operation which removes small amounts of metal from the working surfaces of gear teeth. Its purpose is to correct errors in index, helix angle, tooth profile and eccentricity. The process also improves tooth surface finish and eliminates by means of crowned tooth forms the danger of tooth end load concentrations in service.

It’s been said that the best ideas are often someone else's. But with rebuilt, retrofitted, re-controlled or remanufactured machine tools, buyer beware and hold onto your wallet. Sourcing re-work vendors and their
services can require just as much homework, if not necessarily dollars, as with just-off-the-showroom-floor machines.

Like many Americans, I've been trained with the idea that those who see a problem should be the ones responsible for helping to solve it. If you see
that something is broken, and you know how to fix it, don't wait for your dad, your boss or the government to tell you what to do. Just fix it.

Trying to figure out what’s going on in this crazy economy of ours seems a bit like reading tea leaves—one part pseudoscience and three parts wild conjecture. Of course some pundits are telling us that this bull market has legs, while others insist that we’re due for a major correction. Some pump us up with positive news, while others remind us about scary stuff like the budget deficit, the European financial crisis and unemployment.

This is the first article in an eight-part "reality" series on implementing continuous improvement at Hoerbiger Corporation. Throughout 2013, Dr. Shahrukh Irani will report on his progress applying the job shop lean strategies he developed during his time at Ohio State University.

Heat treating is a critical operation in gear manufacturing. It can make or break the quality of your final product. Yet it is one that frequently gear manufacturers outsource to someone else. Then the crucial question becomes, how do you know you're getting the right heat treater? How can you guarantee your end product when you have turned over this important process to someone else?

Computers are everywhere. It's gotten so that it's hard to find an employee who isn't using one in the course of his or her day - whether he be CEO or salesman, engineer or machinist. Everywhere you look, you find the familiar neutral-colored boxes and bright glowing screens. And despite the gear industry's traditional reluctance to embrace new technology, more and moe of what you find on those screens are gears.

Okay. You've been convinced. You've gritted your teeth and decided to spend the money to launch a company Web site. Everybody from your teenage propeller-head to the girl in the mail room and the salesman in the flashy suit who gave you "such a deal" on Web site services has promised that your site will be the best thing that's happened to your business since the advent of CNC machines.

When the term, “what you see is what you get” is applied in the computer
industry, it means that users or customers are able to see their end
results without the encumbrances of
complicated software code that enables
this function. Software works behind
the scenes ultimately to produce transparency and the desired effects. In
many ways, this concept should be
extended to the relationships that exist
between suppliers and buyers and even
among internal company departments.

Long-time readers of these pages will know that I have always felt strongly about the subject of professional education. There's nothing more important for an individual's career development than keeping up with current technology. likewise, there's nothing more important that a company can do for itself and it employees than seeing to it they have the professional education they need. Giving people the educational tools they need to do their jobs is a necessary ingredient for success.

Whether consumed by its romantic charm or simply a casual fan of its Victorian sensibilities, there’s a growing interest in all things steampunk lately. From books, television and films
to music, art and design, the desire to ‘reclaim technology’ is getting closer and closer to mainstream pop culture. Wherever you find steampunk, you’ll undoubtedly find a gear or two not
far behind.

There are several methods available for improving the quality of spur and helical gears following the standard roughing operations of hobbing or shaping. Rotary gear shaving and roll-finishing are done in the green or soft state prior to heat treating.

Economic times are good right now in America and in the gear industry. We're in the seventh year of an up cycle. The tough shake-outs of the 1980s and early 90s are over. Orders are up. Backlogs are at comfortable levels. We're looking at what promises to be the biggest, most successful trade show in the industry's history coming up in Detroit in October. The most pressing question on the immediate horizon seems to be "How long can the good times go on?"

Broaching is a process in which a cutting tool passes over or through a part piece to produce a desired form. A broach removes part material with a series of teeth, each one removing a specified amount of stock.

High-speed machining using carbide has been used for some decades for milling and turning operations. The intermittent character of the gear cutting process has delayed the use of carbide tools in gear manufacturing. Carbide was found at first to be too brittle for interrupted cutting actions. In the meantime, however, a number of different carbide grades were developed. The first successful studies in carbide hobbing of cylindrical gears were completed during the mid-80s, but still did not lead to a breakthrough in the use of carbide cutting tools for gear production. Since the carbide was quite expensive and the tool life was too short, a TiN-coated, high-speed steel hob was more economical than an uncoated carbide hob.

When you graduated from school and made your way into the world, you probably thought you’d learned everything you needed to know to be successful. But those of us who’ve been out in the workforce for some time know that you
never stop learning.

Open any heat treating journal today and you’re certain to find multiple references (articles, technical papers and/or advertisements) promoting low-pressure carburizing (LPC). The uninformed might breeze by these references thinking it’s the next flash-in-the-pan, but unlike in the past, this time the process has legs.

Interesting gear factoids discovered wasting time on the Net while pretending to be working...The first four-function mechanical calculator was built by the mathematician Gottfried Leibniz in 1694. While not commercially available for nearly 200 years, the design was the basis of many such calculators until well into this century.

Standards are unlike gears themselves: mundane, but complex, ubiquitous and absolutely vital. Standards are a lingua franca, providing a common language with reference points for evaluating product reliability and performance for manufacturers and users. The standards development process provides a scientific forum for discussion of product design, materials and applications, which can lead to product improvement. Standards can also be a powerful marketing tool for either penetrating new markets or protecting established ones.

The struggles of the manufacturing
economy in 2009 are well documented.
Even among those of us with
long careers, most of us have never
seen activity come to a screeching
halt the way it did last year. 2009 was tough on all of us. So, what should we expect in 2010?

This paper presents a unique approach and methodology to define the limits of selection for gear parameters. The
area within those limits is called the “area of existence of involute gears” (Ref. 1). This paper presents the definition and construction of areas of existence of both external and internal gears. The isograms of the constant operating pressure
angles, contact ratios and the maximum mesh efficiency (minimum sliding) isograms, as well as the interference
isograms and other parameters are defined. An area of existence allows the location of gear pairs with certain characteristics. Its practical purpose is to define the gear pair parameters that satisfy specific performance requirements before
detailed design and calculations. An area of existence of gears with asymmetric teeth is also considered.

Listen carefully these days and you'll hear a faint rumbling among the economic masses. It's probably nothing to worry about. It'll most likely go away. It's only the naysayers and skeptics who predict that the end is near. They've been doing to far almost all eight years of our current economic boom, and they've been wrong so far.

Above all, a gear is not just a mechanical transmission, but is developed to a system fulfilling multiple demands, such as clutch integration, selectable output speeds, and controls of highest electronic standards. This paper shows the basics for high-speed gear design and a selection of numerous applications in detailed design and operational needs.

This is the third article in a series exploring the new ISO 6336 gear rating standard and its methods of calculation. The opinions expressed herein are htose of the author as an individual. They do not represent the opinions of any organization of which he is a member.

Air compressors are a good example of industrial machinery with components that rotate at very high speeds, up to 80,000 rpm. They are subject to very high rotational forces and often variable loads. Strong, high-precision gears for the power transmission trains that drive the impellers are critical components of machinery operating under such conditions.

The first part of this article describes the analytical design method developed by the author to evaluate the load capacity of worm gears.
The second part gives a short description of the experimental program and testing resources being used at CETIM to check the basic assumptions of the analytical method; and to determine on gears and test wheels the surface pressure endurance limits of materials that can be used for worm gears.
The end of the article compares the results yielded by direct application of the method and test results.

AGMA's Gear Expo '89 was, by all accounts, a great success, proving again the wisdom of having a trade show devoted exclusively to gearing and gear-related products. Over 1500 people attended the show, and 86 different companies exhibited their goods and services.

The turbines are still spinning.
They’re spinning on large wind farms
in the Great Plains, offshore in the
Atlantic and even underwater where
strong tidal currents offer new energy
solutions. These turbines spin regularly
while politicians and policy makers—
tied up in discussions on tax incentives, economic recovery and a lot of finger pointing—sit idle. Much like the auto and aerospace industries of years past, renewable energy is coping with its own set of growing pains. Analysts still feel confident that clean energy will play a significant role in the future of manufacturing—it’s just not going to play the role envisioned four to five
years ago.

The Millenium Outlook article in the January/February 2000 issue of Gear Technology explored the prevailing attitudes of the gear industry as it stands on the brink of the new millenium through the thoughts and words of some of the industry's leaders. The article also placed the gear industry within the framework of 20th Century history. Joe Arvin, President of Arrow Gear, was interviewed for this article and requested an opportunity to elaborate on his published comments.

Until recently, there was a void in the quality control of gear manufacturing in this country (Ref. 1). Gear measurements were not traceable to the international standard of length through the National Institute of Standards and Technology (NIST). The U.S. military requirement for traceability was clearly specified in the military standard MIL-STD-45662A (Ref. 2). This standard has now been replaced by commercial sector standards including ISO 9001:1994 (Ref. 3), ISO/IEC Guide 25 (Ref, 4), and the U.S. equivalent of ISO/IEC Guide 25 - ANSI/NCSL Z540-2-1997 (Ref. 5). The draft replacement to ISO/IEC Guide 25 - ISO 17025 states that measurements must either be traceable to SI units or reference to a natural constant. The implications of traceability to the U.S. gear industry are significant. In order to meet the standards, gear manufacturers must either have calibrated artifacts or establish their own traceability to SI units.

Following is a report on the R&D findings regarding remediation of high-value, high-demand spiral bevel gears for the UH–60 helicopter tail rotor drivetrain. As spiral bevel gears for the UH–60 helicopter are in generally High-Demand due to the needs of new aircraft production and the overhaul and repair of aircraft returning from service, acquisition of new spiral bevel gears in support
of R&D activities is very challenging. To compensate, an assessment was done of a then-emerging superfinishing method—i.e., the micromachining process (MPP)—as a potential repair technique for spiral bevel gears, as well as a way to enhance their performance and durability. The results are described in this paper.

Many gear companies make parts, build assemblies...and stop there. But, some don't stop; they go a step further and create end-products. Three gear companies have taken that step, and taken on nature with their creations.

In effect, this article continues a previous Gear Technology article, "Modeling Gears In Pro/Engineer," published in the January/February 1999 issue. The previous article discussed drawing involute gear teeth using a program built into the Pro/E software.

Bicyclophiles (OK—not a real word, but you get the idea) around the globe
may very well know the name, but chances are good that most Gear Technology readers have never heard
of Sheldon Brown, AKA—“Gear Ratio,” “Gain Ratio,” “Mouldy Oldie,” “Theory,”
“Quixote,” “Fixit” and some the Addendum team probably missed.

The load capacity rating of gears had its beginning in the 18th century at Leiden University when Prof. Pieter van
Musschenbroek systematically tested the wooden teeth of windmill gears, applying the bending strength formula published by Galilei one century earlier. In the next centuries several scientists improved or extended the formula, and recently a Draft International Standard could be presented.

When hardened steel components are ground, there is always the possibility of damage to the steel in the form of residual stress or microstructural changes. Methods for detecting this sort of damage have always had one or more drawbacks, such as cost, time, complexity, subjectivity, or the use of hazardous chemicals.

Mechanical efficiency is an important index of gearing, especially for epicyclic gearing. Because of its compact size, light weight, the capability of a high speed ratio, and the ability to provide differential action, epicyclic gearing is very versatile, and its use is increasing. However, attention should be paid to efficiency not only to save energy, but sometimes also to make the transmission run smoothly or to avoid a self-locking condition.

Mineral-oil-base lubricants show a significant decrease of kinematic viscosity with rising temperature, as exemplified in Figure 1 by lubricants for vehicle gears. An important attribute of lubricants is their viscosity index (VI), according to DIN/ISO 2909 (Ref. 4). Viscosity index is a calculated coefficient, which characterizes the change of viscosity of lubricants as a function of temperature. A high viscosity index represents a low variation of viscosity due to temperature and vice versa. A low viscosity-temperature-dependence is required for lubricants that are operated at significantly varying temperature conditions, such as vehicle engine and gear lubricants in summer and winter time. This way, the oils remain flowing and pumpable at low temperatures on the one hand; and on the other hand, sufficiently thick lubricant films can be formed at higher temperatures for a safe separation of the surfaces.

Besides Gear Expo 2001, Detroit is home to a museum with an 1896 Durya Motor Wagon, America's first production car; home to a casino in a building that use to be Internal Revenue Service offices; and home to the studio where Diana Ross and the Supremes recorded "Stop in the Name of Love."

Sitting down to write my comments for this issue, one event filled my thoughts-the transformation and uninhibited euphoria that overcame Chicago, and the whole Midwest, by the Bears reaching and winning the Superbowl.

This issue of Gear Technology, The Journal of Gear Manufacturing, marks the end of our second year of publication. As we approach our third year, it is time to review our statement of purpose. Gear Technology's primary goal was and is to be a reference source and a forum for the American Gear industry, and to advance gear technology throughout the world.

Editor's Note: The following article details the advantages of synthetic lubricants in certain applications. However, the user should be aware of certain design issues arising from the extract chemistry of the synthetic. For example, some synthetics may have low solvency for additives. Others may not be compatible with mineral oils or nonmetallic components such as seals and paints. Some synthetics may absorb water and may not have the same corrosion resistance as mineral oils. Finally, the user should consider biodegradability or toxicity before switching to any new lubricant. Many of these concerns are present in petroleum-based lubricants as well, so consult a lubrication specialist before specifying a lubricant.

Most anyone that has been in the
gear industry—or any machining and
tooling oriented business, for that
matter—is probably at least somewhat
familiar with the Roto-Flo workhorse
line of hydraulic-actuated spline and
thread rolling machines. After all,
they’ve been at it for decade

We'd like to thank our friends down at Sanderson Brothers Pty. Ltd., Thomastown, Australia, for bringing the work of Capt. S. Bramley-Moore to our attention. So, without further ado, we offer you the following poem to help you keep your gear formulae straight.

Modern manufacturing processes have become an ally of the product designer in producing higher quality, higher performing components in the transportation industry. This is particularly true in grinding systems where the physical properties of CBN abrasives have been applied to improving cycle times, dimensional consistency, surface integrity and overall costs. Of these four factors, surface integrity offers the greatest potential for influencing the actual design of highly stressed, hardened steel components.

This issue's editorial is a reprint of the keynote address given by Michael Goldstein at the Computer Aided Gear Design Seminar held at the University of Northern Iowa, Cedar Falls, IA on November 9, 1987.

Gear manufacturers are moving into an era that will see changes in both engineering practices and industry
standards as new end-products evolve. Within the traditional automotive
industry, carbon emission reduction
legislation will drive the need for higher levels of efficiency and growth in electric and hybrid vehicles.
Meanwhile, the fast growing market of wind turbines is already opening up a whole new area of potential for gearbox manufacturers, but this industry is one that will demand reliability, high levels of engineering excellence and precision manufacturing.

Carburized helical gears with high retained austenite were tested for surface contact fatigue. The retained austenite before test was 60% and was associated with low hardness near the case's surface. However, the tested gears showed good pitting resistance, with fatigue strength greater than 1,380 MPa.

In his Handbook of Gear Design (Ref.1), Dudley states (or understates): "The best gear people around the world are now coming to realize that metallurgical quality is just as important as geometric quality." Geometric accuracy without metallurgical integrity in any highly stressed gear or shaft would only result in wasted effort for all concerned - the gear designer, the manufacturer, and the customer - as the component's life cycle would be prematurely cut short. A carburized automotive gear or shaft with the wrong surface hardness, case depth or core hardness may not even complete its basic warranty period before failing totally at considerable expense and loss of prestige for the producer and the customer. The unexpected early failure of a large industrial gear or shaft in a coal mine or mill could result in lost production and income while the machine is down since replacement components may not be readily available. Fortunately, this scenario is not common. Most reputable gear and shaft manufacturers around the world would never neglect the metallurgical quality of their products.

At the time I'm writing this editorial, the new year is barely two weeks old. The air and the papers are still full of those inevitable end-of-the-year estimates of how far we've come in one area or another and how far we have to go. Analyses of the future, both grim and humorous, abound. There are even more of these laundry lists of PROBLEMS TO BE SOLVED IMMEDIATELY than usual, since a new president will be inaugurated in a week or so. Everyone had advice for George Bush on what to do first and how to do it. Some of the advice is sound, and I hope he's listening; however, reading all these position papers can be a depressing exercise.

The objective of this paper is to demonstrate that transmission gears
of rotary-wing aircraft, which are typically scrapped due to minor foreign
object damage (FOD) and grey staining, can be repaired and re-used with
signifi cant cost avoidance. The isotropic superfinishing (ISF) process is used to repair the gear by removing surface damage. It has been demonstrated
in this project that this surface damage can be removed while maintaining
OEM specifications on gear size, geometry and metallurgy. Further, scrap
CH-46 mix box spur pinions, repaired by the ISF process, were subjected to
gear tooth strength and durability testing, and their performance compared
with or exceeded that of new spur pinions procured from an approved
Navy vendor. This clearly demonstrates the feasibility of the repair and
re-use of precision transmission gears.

Myth No. 1: Oil Is Oil. Using the wrong oil is a common cause of gear failure. Gears require lubricants blended specifically for the application. For example, slow-speed spur gears, high-speed helical gears, hypoid gears and worm gears all require different lubricants. Application parameters, such as operating speeds, transmitted loads, temperature extremes and contamination risks, must be considered when choosing an oil. Using the right oil can improve efficiency and extend gear life.

Much has happened since we last reported on the malfunctioning solar array rotary joint (SARJ) attached to the International Space Station. Space shuttle Endeavour dropped in for a two-week visit in November during which repairs were made and invaluable data collected.

Richard Spens has been rebuilding antique machine tools for nearly a decade. He is drawn to the ornate architecture and fascinated by the open design that allows you to see inside a machine as it operates. "Working with machines has been a lifelong thing with me," said Spens, now a design engineer. "I started building steam engines when I was 10 years old." What he's working on now, however, is bigger than any steam engine or machine tool. In rural Livonia, Michigan, Spens is converting an old dairy barn into an accurate recreation of a turn-of-the-century, belt driven gear shop. It's an outgrowth of his interest in antique machine tools and, he feels, a way to stem the tide that is costing America so many manufacturing and skilled trade jobs.

When you're 15, you're filled with confidence and exuberance, and you have a future full of potential and room for growth. You're ready to take on the world. Gear Technology began publishing exactly 15 year ago, with the May/June 1984 issue, and the magazine has grown in many ways since then.

For years, politicians, educators and business leaders have generated various ideas to revitalize U.S. manufacturing and engineering. These include manufacturing initiatives, internal training programs and an emphasis on science, technology,
engineering and mathematics (STEM) in the classroom. The declining expertise in these fields, however, continues to
be a growing problem in every facet of manufacturing and engineering.

Mission: Competing to Win
Like a lot of people, I grew up seeing the world as fairly flat and believing that everything of importance happened in Texas. As I grew older, my outlook grew to include the United States, Canada, and Mexico. The rest of the world did not seem very important, if it existed at all. Unfortunately, I was not alone in this very narrow view. Many other in the gear business shared this perception.

Many potential problems are not apparent when using new induction heat treating systems. The operator has been trained properly, and setup parameters are already developed. Everything is fresh in one's mind. But as the equipment ages, personnel changes or new parts are required to be processed on the old equipment ages, personnel changes or new parts are required to b processed on the old equipment, important information can get lost in the shuffle.

Joe Garfien came to America in 1928 to play soccer. He also learned to cut gears and build a business.
"When I came here [to America] I came in on a Friday, and I had to go work on Monday, so I found a job at Perfection Gear...and that's how I got started in gears."

Notes from Detroit...Overall, Gear Expo 97, the AGMA biennial trade show, was a success. While attendance may not have been what some people had hoped for, the quality of the attendees was high. Serious buyers came and brought their checkbooks.

The other day I went to Starbuck’s and ordered
my usual four shots of espresso, straight up. I know
what you’re thinking: that’s a lot of caffeine, especially for someone
as naturally energetic as I am. But after years and years, I
may have built up a tolerance to the caffeine. I picked up the
espresso habit as a much younger man, when I worked for
Daldi & Matteucci (DEMM) in Italy back in the ’70s. And I’ve
stuck with it ever since.

It takes confidence to be the first to invest in new manufacturing technology. But the payback can be significant. That has been the experience at the Ford Motor Company's Transmission & Chassis Division plant at Indianapolis, IN, which boasts the world's first production application of dry hobbing.

Many people in the gear industry have heard of skiving, a process wherein solid carbide or inserted carbide blade hobs with 15 - 60 degrees of negative rake are used to recut gears to 62 Rc. The topic of this article is the use of neutral (zero) rake solid carbide hobs to remove heat treat distortion, achieving accuracies of AGMA 8 to AGMA 14, DIN 10-5 and improving surface finish on gears from 8 DP - 96 DP (.3 module - .26 m.).

More and more gear shops are wrestling with the issue of whether or not solid modeling is right for their gear design work. The Q & A Page of The Gear Industry Home Page has had numerous questions asking how to model gears in solid modeling applications such as AutoCAD, Solidworks and Pr/Engineer. Given the problems people have been having, we are presenting the step-by-step process for modeling gears in Pr/Engineer, but first we thought it would be a good idea to explore the question of whether or not you should even try to design gears using Pro/Engineer or any other 3D solid modeling program.

ISO 6336 Calculation of Load Capacity of Spur and Helical Gears was published in 1997 after 50 years of effort by an international committee of experts whose work spanned three generations of gear technology development. It was a difficult compromise between the existing national standards to get a single standard published which will be the basis for future work. Many of the compromises added complication to the 1987 edition of DIN 3990, which was the basic document.

This article discusses applications of statistical process capability indices for controlling the quality of tooth geometry characteristics, including profile and lead as defined by current AGMA-2015, ISO-1328, and DIN-3960 standards. It also addresses typical steps to improve manufacturing process capability for each of the tooth geometry characteristics when their respective capability indices point to an incapable process.

October is the time. Detroit is the place. AGMA Gear Expo '91 is the event. Cobo Center in downtown Detroit is where you will want to be in October if you have any interest in gear products, manufacturing, or research.

When the steam engine became available for industrial use at the end of the eighteenth century, it was mainly used for driving plunger-pumps, such as those used in English coal mines. The stream engine's piston drove a lever, that reciprocating motion of which drove the pump plunger. Called the "Beam Machine," this mechanism needed a lot of space, had many parts, and was difficult to install because the engine and the pump had to be properly aligned.

Roughly 100 years ago, Cornelius J. Brosnan of Springfield, Massachusetts, invented and received the first U.S. patent for a paper clip. At about the same time, his fellow inventors were coming up with such marvels as the zipper, the safety razor and the typewriter.

The performance of metal surfaces can be dramatically enhanced by the thermal process of rapid surface melting and re-solidification (RMRS). When the surface of a metal part (for instance, a gear) is melted and re-solidified in less than one thousandth of a second, the resulting changes in the material can lead to:
Increased wear and corrosion resistance,
Improved surface finish and appearance,
Enhanced surface uniformity and purity, and
Sealing of surface cracks and pores.

A great deal of attention has been paid to the decline of manufacturing in America, and I've been accused of being a town crier since the 1980s, when I began to see our nation lose its edge to foreign competition. My concerns have proven well-founded.

Recently, a new type of hob with carbide inserts has been introduced, providing higher cutting speeds, longer tool life and higher feed rates when compared to re-grindable, high-speed steel hobs. But with this kind of hob, new challenges occur due to positional errors of the cutting edges when mounted on the tool. These errors lead to manufacturing errors on the gear teeth which must be controlled. In this paper, the tooth quality of a gear manufactured by hobs with different quality classes is analyzed using a simulation model in combination with Monte Carlo methods.

Geoffrey Parrish has updated and expanded his previous book: The Influence of Microstructure on the Properties of Case-Carburized Components. It now contains at least twice the material. References and bibliography include 449 citations.

No matter what business you're in, you need customers. More importantly, you need customers who can and want to pay for your goods or services. It's in our best interest to do everything we can to make sue our customers are successful with the products or services they buy from us, as I believe that our wages are paid not by our companies but by their customers.

We've contacted many of the gear industry's leading suppliers to find out what they'll be showing at Gear Expo 99. Booth numbers are current as of July 31, 1999, but they are subject to change. A current list of exhibitors and booth information is available at the AGMA Web site at www.agma.org.

Some years back, most spiral bevel gear sets were produced as cut, case hardened, and lapped. The case hardening process most frequently used was and is case carburizing. Many large gears were flame hardened, nitrided, or through hardened (hardness around 300 BHN) using medium carbon alloy steels, such as 4140, to avoid higher distortions related to the carburizing and hardening process.

Rodgers and Hammerstein produced some of America's most memorable and lasting songs in musical theater. Lyricist Oscar Hammerstein II once said of composer Richard Rodgers, "I hand him a lyric and get out of his way," Hammerstein knew what Rodgers was good at, and vice versa, and each trusted his partner. Their partnership was so successful that you can scarcely think of one man without the other.

This article offers an overview of the practical design of a naval gear for combined diesel or gas turbine propulsion (CODOG type). The vibration performance of the gear is tested in a back-to-back test. The gear presented is a low noise design for the Royal Dutch Navy's LCF Frigate. The design aspects for low noise operation were incorporated into the overall gear system design. Therefore, special attention was paid to all the parameters that could influence the noise and vibration performance of the gearbox. These design aspects, such as tooth corrections, tooth loading, gear layout, balance, lubrication and resilient mounting, will be discussed.

Planetary gear transmissions are compact, high-power speed reducers that use parallel load paths. The range of possible reduction ratios is bounded from below and above by limits on the relative size of the planet gears. For a single-plane transmission, the planet gear has no size of the sun and ring. Which ratio is best for a planetary reduction can be resolved by studying a series of optimal designs. In this series, each design is obtained by maximizing the service life for a planetary transmission with a fixed size, gear ratio, input speed, power and materials. The planetary gear reduction service life is modeled as a function of the two-parameter Weibull distributed service lives of the bearings and gears in the reduction. Planet bearing life strongly influences the optimal reduction lives, which point to an optimal planetary reduction ratio in the neighborhood of four to five.

Aurstempered irons and steels offer the design engineer alternatives to conventional material/process combinations. Depending on the material and the application, austempering may provide the producers of gear and shafts with the following benefits: ease of manufacturing, increased bending and/or contact fatigue strength, better wear resistance or enhanced dampening characteristics resulting in lower noise. Austempered materials have been used to improve the performance of gears and shafts in many applications in a wide range of industries.

Does anyone know where we can find a gear-shaped fruitcake?
It's the holiday season again, and the Addendum staff has many friends. We'd like to get each of them the perfect holiday gift, something the demonstrates thought, caring and good will. Of course, we're looking for gifts with meaning, and for us, that can only mean gears.

Hoechst Technical Polymers has expanded its interests in plastic gears with the introduction of the new Plastic Gear Evaluation and Research machine P-Gear. The machine is the centerpiece of the company's continuing efforts to promote and develop the use of plastic gears in higher-powered applications.

The quality of the material used for highly loaded critical gears is of primary importance in the achievement of their full potential. Unfortunately, the role which material defects play is not clearly understood by many gear designers. The mechanism by which failures occur due to material defects is often circuitous and not readily apparent. In general, however, failures associated with material defects show characteristics that point to the source of the underlying problem, the mechanism by which the failure initiated, and the manner in which it progressed to failure of the component.

Recent trends in gear cutting technology have left process engineers searching for direction about which combination of cutting tool material, coating, and process technology will afford the best quality at the lowest total cost. Applying the new technologies can have associated risks that may override the potential cost savings. The many interrelated variables to be considered and evaluated tend to cloud the issue and make hobbing process development more difficult.

Face-milled hypoid pinions produced by the three-cut, Fixed Setting system - where roughing is done on one machine and finishing for the concave-OB and convex-IB tooth flanks is done on separate machines with different setups - are still in widespread use today.

Plastic gears and transmissions require a different design approach than metal transmissions. Different tools are available to the plastic transmission designer for optimizing his geared product, and different requirements exist for inspection and testing.
This paper will present some of the new technology available to the plastic gear user, including design, mold construction, inspection, and testing of plastic gears and transmissions.

This is the fourth and final article in a series exploring the new ISO 6336 gear rating standard and its methods of calculation. The opinions expressed herein are those of the author as an individual. They do not represent the opinions of any organization of which he is a member.

Users of gear-cutting tools probably do not often consciously consider the raw material from which those hogs, broaches or shavers are made. However, a rudimentary awareness of the various grades and their properties may allow tool users to improve the performance or life of their tools, or to address tool failures. The high-speed steel from which the tool is made certainly is not the only factor affecting tool performance, but as the raw material, the steel may be the first place to start.

Base helix error - the resultant of lead and profile errors is the measured deviation from the theoretical line of contact (Fig. 1). It can be measured in the same way that lead error on a spur gear is measured, namely, by setting a height gage to height H based on the radial distance r to a specified line of contact (Fig. 2), rotating the gear so as to bring a tooth into contact with the indicator on the height gage, and then moving the height gage along two or more normals to the plane of action. The theoretical line of contact on helical gear must be parallel to the surface plate, which is attained by mounting the gear on a sine bar (Fig. 3).

Every once in a while something happens to fundamentally change the nature of your business. Despite the best of intentions and the most careful planning, there's no way we can anticipate every event. What do you do, for example, when your two biggest competitors merge, when the economy collapses in the region that imports your products or when key employees leave your company? Your reactions may make the difference between success and struggling to survive.

In the approximately 15 years that I have been writing editorials for Gear Technology, I've purposely avoided certain topics. Sex, religion and my own used gear machinery business are among the subjects that have always been off limits. But with this issue, I'm going to break one of my long-standing taboos by talking politics.

An analysis of possibilities for the selection of tool geometry parameters was made in order to reduce tooth profile errors during the grinding of gears by different methods. The selection of parameters was based on the analysis of he grid diagram of a gear and a rack. Some formulas and graphs are presented for the selection of the pressure angle, module and addendum of the rack-tool. The results from the grinding experimental gears confirm the theoretical analysis.

I must admit that after thumbing through the pages of this relatively compact volume (113 pages, 8.5 x 11 format), I read its three chapters(theory of gearing, geometry and technology, and biographical history) from rear to front. It will become obvious later in this discussion why I encourage most gear engineers to adopt this same reading sequence!

This section is dedicated to what's new and what's happening in the world of gear inspection and metrology. Here you will find news about products, companies and organizations, services and events affecting the gear inspection and metrology industry.

Would you like to be able to see the condition of the gears in your transmissions without having to open the box and physically examine them? There is a way, and not too many people know about it. It's called Wear Particle Analysis, or ferrography, and it is just starting to get noticed.

Gear design and specification are not one and the same. They are the first two steps in making a gear. The designer sits down and mathematically defines the gear tooth, working with the base pitch of the gear, the pressure angle he wants to employ, the number of teeth he wants, the lead, the tooth thickness, and the outside, form and root diameters. With these data, the designer can create a mathematical model of the gear. At this stage, he will also decide whether the gear will be made from existing cutting tools or whether new tools will be needed, what kind of materials he will use, and whether or not he will have the gear heat treated and finished.

Traditionally, profile and lead inspections have been indispensable portions of a standard inspection of an involute gear. This also holds true for the worm of a worm gear drive (Ref. 1). But the inspection of the profile and the lead is rarely performed on a worm wheel. One of the main reasons is our inability to make good definitions of these two elements (profile and lead) for the worm wheel. Several researchers have proposed methods for profile and lead inspections of a worm wheel using CNC machines or regular involute and lead inspections of a worm wheel using CNC machines or regular involute measuring machines. Hu and Pennell measured a worm wheel's profile in an "involute" section and the lead on the "pitch" cylinder (Ref. 2). This method is applicable to a convolute helicoid worm drive with a crossing angle of 90 degrees because the wheel profile in one of the offset axial planes is rectilinear. This straight profile generates an involute on the generated worm wheel. Unfortunately, because of the hob oversize, the crossing angle between the hob and the worm wheel always deviates from 90 degrees by the swivel angle. Thus, this method can be implemented only approximately by ignoring the swivel angle. Another shortcoming of this method is that there is only one profile and one lead on each flank. If the scanned points deviated from this curve, it produced unreal profile deviation. Octrue discussed profile inspection using a profile checking machine (Ref. 3).

Although the cultures and areas of expertise of Solomon and Sun Tzu are worlds apart, the two offer similar opinions on the importance of seizing the moment. Their ancient wisdom may have increasing relevance to modern manufacturers in a global economy, particularly those contemplating whether now is the time to invest in capital equipment.

During the last decade, industrial gear manufacturers, particularly in Europe, began to require documentation of micropitting performance before approving a gear oil for use in their equipment. The development of micropitting resistant lubricants has been limited both by a lack of understanding of the mechanism by which certain lubricant chemistry promotes micropitting and by a lack of readily available testing for evaluation of the micropitting resistance of lubricants. This paper reports results of two types of testing: (1) the use of a roller disk machine to conduct small scale laboratory studies of the effects of individual additives and combinations of additives on micropitting and (2) a helical gear test used to study micropitting performance of formulated gear oils.

Designers are constantly searching for ways to reduce rotocraft drive system weight. Reduced weight can increase the payload, performance, or power density of current and future systems. One example of helicopter transmission weight reduction was initiated as part of the United States Army Advanced Rotocraft Transmission program. This example used a split-torque, face-gear configuration concept (Ref. 1). compared to a conventional design with spiral-bevel gears, the split-torque, face-gear design showed substantial weight savings benefits. Also, the use of face gears allows a wide-range of possible configurations with technical and economic benefits (Ref. 2).

Normandy overwhelmed me when I first went there several years ago. I was sobered by the sea of white crosses in the cemeteries, I was inspired by the memorials and their tales of courageous soldiers battling impossible odds, and I was horrified by the visions of carnage that came to me as I stood on the scarred beaches of one of the most significant conflicts in human history.

The market demand for gear manufacturers to transmit higher torques via smaller-sized gear units inevitably leads to the use of case-hardened gears with high manufacturing and surface quality. In order to generate high part quality, there is an increasing trend towards the elimination of the process-induced distortion that occurs during heat treatment by means of subsequent hard finishing.

In general, bevel gears and curvic couplings are completely different elements. Bevel gears rotate on nonintersecting axis with a ratio based on the number of teeth. Curvic couplings work like a clutch (Fig. 1).

This report presents some interim results from an ongoing project being performed by INFAC, the Instrumented Factory for Gears. The purposes of this initial phase of the project were to demonstrate the feasibility of robotic automated deburring of aerospace gears, and to develop a research agenda for future work in that area.

Noncircular gearing is not new. There are well-documented articles covering standard and high order elliptical gears, sinusoidal gears, logarithmic spiral gears, and circular gears mounted eccentrically. What these designs have in common is a pitch curve defined by a mathematical function. This article will cover noncircular gearing with free-form pitch curves, which, of course, includes all the aforementioned functions. This article also goes into the generation of teeth on the pitch curve, which is not usually covered in the technical literature. Needless to say, all this is possible only with the help of a computer.

For high-quality carburized, case hardened gears, close case carbon control is essential.
While tight carbon control is possible, vies on what optimum carbon level to target can be wider than the tolerance.

The tooth-by-tooth, submerged induction hardening process for gear tooth surface hardening has been successfully performed at David Brown for more than 30 years. That experience - backed up by in-depth research and development - has given David Brown engineers a much greater understanding of, and confidence in, the results obtainable from the process. Also, field experience and refinement of gear design and manufacturing procedures to accommodate the induction hardening process now ensure that gears so treated are of guaranteed quality.

The Gear Research Laboratory of the University of Illinois at Chicago is home to a unique tribute to gear pioneers from around the world, the Gallery of Fame. The gallery is the brainchild of the laboratory director, Professor Faydor L. Litvin. The Gallery was begun in 1994 an dis a photographic tribute to those gear company founders, inventors and researchers who devoted their careers to the study and development of gears.

Chicken Run - the summer that used stop-motion clay figures - is about a group of chickens laying a plan to escape from their farm before they're turned into chicken pies. Distributed by Steven Spielberg's Dream Works, Chicken Run is also about a group of specially-made worms and wheels.

It used to be that gear manufacturers wanting to perform analytical gear inspection required at least three machines to do so: The lead measuring instrument, the tooth space comparator and the involute checking instrument. In the beginning, these machines were mechanically driven. Over the years, the manufacturers of analytical gear inspection equipment have combined these functions - and a host of others.

The goal of gear drive design is to transit power and motion with constant angular velocity. Current trends in gear drive design require greater load carrying capacity and increased service life in smaller, quieter, more efficient gearboxes. Generally, these goals are met by specifying more accurate gears. This, combined with the availability of user-friendly CNC gear grinding equipment, has increased the use of ground gears.

Designing a gear set implies a considerable effort in the determination of the geometry that fulfills the requirements of load capacity, reliability, durability, size, etc. When the objective is to design a new set of gears, there are many alternatives for the design, and the designer has the freedom to choose among them. Reverse engineering implies an even bigger challenge to the designer, because the problem involves already manufactured gears whose geometry is generally unknown. In this case, the designer needs to know the exact geometry of the actual gears in order to have a reference for the design.

Clocks with wooden gears? In these days of gears made from plastic, steel and exotic materials; it is a little unusual to hear about a practical application for wooden gears. But that is exactly what David Scholl, the owner of Changing Times, a Harlingen, TX, clockmaker is offering us.

Gear noise associated with tooth surface topography is a fundamental problem in many applications. Operations such as shaving, gear grinding and gear honing are usually used to finish the gear surface. Often, gears have to be treated by a combination of these operations, e.g. grinding and honing. This is because gear honing operations do not remove enough stock although they do create a surface lay favorable for quiet operation. See Fig. 1 for typical honing process characteristics. Gear grinding processes, on the other hand, do remove stock efficiently but create a noisy surface lay.

It’s not too often a trade show so far
surpasses organizers’ expectations for
size that it must be relocated. This was just the dilemma the American Wind
Energy Association (AWEA) faced with the Windpower 2009 Conference and Exhibition, which was originally
scheduled to take place in Minneapolis,
but will now be held at McCormick
Place, Chicago.

In January of this year we at Gear Technology got hip to the fact-in un-hip, belated fashion - that we needed a Blog Site and someone to do the blogging. Lucky for us, we already had that someone right here - in plain sight. That someone was Charles D. Schultz, P.E.

Long before oil, climate change and energy demand were making headlines in Washington, Minnesota State Auditor Rebecca Otto and her husband installed a wind energy system on their property in Minnesota.

Contact fatigue and bending fatigue are two main failure modes of steel gears, while surface pitting and spalling are two common contact fatigue failures -- caused by alternating subsurface shear stresses from the contact load between two gear mates. And when a gear is in service under cyclic load, concentrated bending stresses exist at the root fillet -- the main driver of bending fatigue failures. Induction hardening is becoming an increasingly popular response to these problems, due to its process consistency, reduced energy consumption, clean environment and improved product quality -- but not without issues of its own (irregular residual stresses and bending fatigue). Thus a new approach is proposed here that flexibly controls the magnitude of residual stress in the regions of root fillet and tooth flank by pre-heating prior to induction hardening. Using an external spur gear made of AISI 4340 as an example, this new concept/process is demonstrated using finite element modeling and DANTE commercial software.

Dressable vitrified bond CBN grinding tools combine the advantages of other common tool systems in generating gear grinding. Yet despite those technological advantages, there is only a small market distribution of these grinding tools due to high tool costs. Furthermore, scant literature exists regarding generating gear grinding with dressable CBN. This is especially true regarding the influence of the grinding tool system on manufacturing-related component properties. The research objective of this report is to determine the advantages of dressable CBN tools in generating gear grinding.

When it comes to purchasing gear lubricants, many people on both the sales and purchasing side decide to play the numbers game. The person with the most numbers, or the biggest numbers, or the lowest numbers, must have the best product - right? Wrong; gear oil selection is not a game, and numbers alone cannot determine the right product for an application.

Precision components (industrial bearing races and automotive gears) can distort during heat treatment due to effects of free or unconstrained oil quenching. However, press quenching can be used to minimize these effects. This quenching method achieves the relatively stringent geometrical requirements stipulated by industrial manufacturing specifications. As performed on a wide variety of steel alloys, this specialized quenching technique is presented here, along with a case study showing the effects of prior thermal history on the distortion that is generated during press quenching.

The Addendum team thought it fitting to celebrate George Orwell's 1984 with the 30th Anniversary of Gear Technology. We do not condone the extreme tactics discussed in this fictional press release unless instructed by the proper authorities.

It has long been known that the skiving
process for machining internal gears is
multiple times faster than shaping, and
more flexible than broaching, due to skiving's continuous chip removal capability. However, skiving has always presented a challenge to machines and tools. With the relatively low dynamic stiffness in the gear trains of mechanical machines, as well as the fast wear of uncoated cutters, skiving of cylindrical gears never achieved acceptance in shaping or hobbing, until recently.

A recent U.S. Army Tank-Automotive Command project, conducted by Battelle's Columbus Laboratories. successfully developed the methodology of CAD/CAM procedures for manufacturing dies (via EDM) for forging spiral bevel gears. Further, it demonstrated that precision forging of spiral bevel gears is a practical production technique.
Although no detailed economic evaluation was made in this study, it is expected that precision forging offers an attractive alternative to the costly gear cutting operations for producing spiral bevel gears.

The Society of Manufacturing Engineers is sponsoring an educational program on the "Fundamentals of Industrial and Manufacturing Engineering," to be held January 28-30, 1986 at the Sheraton-Sand Key Resort in Clear-water Beach, Florida.

Gear Expo provides an opportunity to learn from the industry's experts by walking the aisles and talking to exhibitors. Visitors to Gear Expo 2001 also can take advantage of some formal training and educational opportunities sponsored by AGMA and SME.

When you to to IMTS, you expect to see hoopla. The mass of machines and bodies gathered in one place should create an unmistakable level of energy and enthusiasm. IMTS 2000 seemed uncharacteristically quiet...

In a modern truck, the gear teeth are among the most stressed parts. Failure of a tooth will damage the transmission severely. Throughout the years, gear design experience has been gained and collected into standards such as DIN (Ref. 1) or AGMA (Ref. 2). Traditionally two types of failures are considered in gear design: tooth root bending fatigue, and contact fatigue. The demands for lighter and more silent transmissions have given birth to new failure types. One novel failure type, Tooth Interior Fatigue Fracture (TIFF), has previously been described by MackAldener and Olsson (Refs. 3 & 4) and is further explored in this paper.

I'm a big believer in the value of IMTS as a marketplace where gear manufacturers can go and look at the latest machine tools and processes; compare hobbing machines, gear grinders and inspection equipment; see turning, milling or grinding machines in action; and ask questions of the various vendors all in one place. This year's IMTS promised to be the biggest ever, and I have no doubt that it will be a valuable experience to those who go there looking for ways to improve the way they manufacture products.

Top Secret
Code Name: Ginger
Mission: Design, prototype and test a transmission for a new device. The transmission must be compact and efficient. It should have almost no backlash, and it must be able to operate in both forward and reverse. Most importantly, the transmission must be quiet. In fact, it shouldn't sound like a transmission at all. It should blend in with the environment and sound like music or the wind. This mission, should you choose to accept it, is top secret. Not even your employees can know what you're working on...

It isn't for everyone, but...
Within the installed base of modern CNC gear profile grinding machines (approximately 542 machines worldwide), grinding from the solid isn't frequent, but a growing number of gear profile grinder users are applying it successfully using CBN-plated wheels.

Soon upon setting down in
this beautiful, former (43 B.C.)
Roman Colony that is now the City of Lyon, I was careening to my hotel, Mach I-plastered to the back seat of a sleek, shinyblack Mercedes taxi, when I realized I was staring at - zut
alors? - cornfields!

Mike Viney's curiosity about the evolving designs of apple parers began after reading the article, "There's a Fascination in Apple Parers" by Marion
Levy, which appeared in the second edition of Linda Campbell's 300 Years of Kitchen Collectibles.

Thousands of gear industry professionals will converge October 24-27 in Nashville, TN, for Gear Expo 99, the industry's biennial collection of the latest in gear manufacturing technology. With nearly 50,000 square feet of exhibit space sold more than two months in advance of the show, this year's Gear Expo will offer visitors more opportunity for supplier comparison than ever before. As of July 20, 166 suppliers of equipment, tooling, services and precision gear products were scheduled to participate, with as many as 20 additional booths yet to be sold, according to AGMA vice president and Gear Expo show manager Kurt Medert. The largest previous Gear Expo was held in 1997 in Detroit, with 43,100 square feet of exhibit space and 161 exhibitors.

If you think Y2K will mean the end of the world, forget it. General Vladimir Dvorkin recently said, "I'd like to apologize beforehand if I fail to realize someone's hopes for the Apocalypse." Te general was, of course, discussing Russian nuclear missiles, making the point that they are not going to launch or detonate when the calendar rolls over to January 1, 2000. General Dvorkin's American counterparts are similarly optimistic. While all that is a relief, it raises the question: will Y2K be as kind to the rest of society? And more specifically, will it be as kind to the gear industry? According to AGMA's president, Joe Franklin, the answer is a resounding "yes." According to Franklin, the AGMA Board considers Y2K a non-issue within an industry that is well ahead of others in its preparedness for January 1, 2000. But is it really? Does the gear industry understand the problem any better than other sectors of society? It's a relief to know that the nuclear bombs are not likely to fall within the first moments of the year 2000, but how about the computers and machines that keep the worldwide economy together?

It is with great anticipation that we move closer to AGMA's Fall Technical Conference and Gear Expo '87, which is being held on Oct. 4-6 in Cincinnati, OH. This bold undertaking by both AGMA and the exhibitors in the Expo's 160 booths is an attempt to make a major change in the industry's approach to the exposition of gear manufacturing equipment. By combining the Expo with the Fall Technical Conference, those involved in gear manufacturing will have the opportunity to review the latest equipment, trends, and most innovative ideas, while keeping up with the newest technology in the industry.

In the May/June Issue of your excellent magazine. Mr. Stan Jakuba discusses a serious problem, not only for the gear industry, but any machinery where fluctuating torque is encountered.
I would like to make the following comments to his article...

I received a letter from Mr. G. W. Richmond, Sullivan Machinery Company, N.H., in which in addition to correcting
mistyping, he made several suggestions
concerning my article "General Equations
for Gear Cutting Tool Calculations."

These lines, interesting enough, are from the notebooks of an artist whose images are part of the basic iconography of Western culture. Even people who have never set foot in a museum and wouldn't know a painting by Corregio from a sculpture by Calder, recognize the Mona Lisa. But Leonardo da Vinci was much more than an artist. He was also a man of science who worked in anatomy, botany, cartography, geology, mathematics, aeronautics, optics, mechanics, astronomy, hydraulics, sonics, civil engineering, weaponry and city planning. There was little in nature that did not interest Leonardo enough to at least make a sketch of it. Much of it became a matter of lifelong study. The breadth of his interests, knowledge, foresight, innovation and imagination is difficult to grasp.

"We're taking over," says Art Milano. It's a bold statement from the engineering manager of Seitz Corporation, one of the largest manufacturers of injection molded plastic gears, but Milano has reason for his optimism. Plastic gears are big business-probably bigger than most gear industry "insiders" realize.

Rochester, NY - Gleason Corporation has acquired the assets of Hurth Maschinen and Werkzeuge GmbH, the designer and builder of cylindrical (parallel-axis) gear-making machinery and tooling based in Munich, Germany. The addition of Hurth gear shaving machines and tooling and gear honing machines will further broaden Gleason's expanding product line for manufacturers of cylindrical gears.

Flank breakage is common in a number of cylindrical and bevel gear applications. This paper introduces a relevant, physically based calculation method to evaluate flank breakage risk vs. pitting
risk. Verification of this new method through testing is demonstrably shown.

Carburized gears have higher strengths and longer lives compared with induction-hardened or quench-tempered gears. But in big module gears, carburizing heat-treatment becomes time-consuming and expensive and sometimes cannot achieve good hardness due to the big mass-effect. Also, it is not easy to reduce distortion of gears during heat treatment.

The traditional way of controlling the quality of hypoid gears' tooth flank form is to check the tooth flank contact patterns. But it is not easy to exactly judge the tooth flank form quality by the contact pattern. In recent years, it has become possible to accurately measure the tooth flank form of hypoid gears by the point-to-point measuring method and the scanning measuring method. But the uses of measured data of the tooth flank form for hypoid gears have not yet been well developed in comparison with cylindrical involute gears. In this paper, the tooth flank form measurement of generated face-milled gears, face-hobbed gears and formulate/generated gears are reported. The authors discuss the advantages and disadvantages of scanning and point-to-point measuring of 3-D tooth flank forms of hypoid gears and introduce some examples of uses of measured data for high-quality production and performance prediction.

Carbon steels have primarily been used to manufacture aerospace gears due to the steels' mechanical characteristics. An alloyed low carbon steel is easily case-hardened to obtain a hard wear surface while maintaining the ductile core characteristics. The microstructure achieved will accept the heavy loading, shocks, and elevated temperatures that gears typically experience in applications. The carbon steel machinability allows for general machining practices to be employed when producing aerospace gears versus the more advanced metal removal processes required by stainless and nickel-based alloys.

Gear pitting is one of the primary failure modes of automotive transmission gear sets. Over the past years, many alternatives have been intended to improve their gear surface durability. However, due to the nature of new process development, it takes a length of time and joint efforts between the development team and suppliers to investigate and verify each new approach.

In this article, equations for finding profile and base pitch errors with a micrometer are derived. Limitations of micrometers with disc anvils are described. The design of a micrometer with suitable anvils is outlined.

Computer technology has touched all areas of our lives, impacting how we obtain airline tickets, purchase merchandise and receive medical advice. This transformation has had a vast influence on manufacturing as well, providing process improvements that lead to higher quality and lower costs. However, in the case of the gear industry, the critical process of tooth contact pattern development for spiral bevel gears remains relatively unchanged.

This paper reviews the necessity for detailed specification, design and manufacture to achieve required performance in service. The precise definition of duty rating and a thorough understanding of the environmental conditions, whether it is in a marine or industrial application, is required to predict reliable performance of a gearbox through its service life. A case study relating to complex marine gears and other general practice is presented to review the techniques used by Allen Gears to design and develop a gearbox that integrates with the requirements of the whole machinery installation. Allen Gears has considerable experience in the design of a variety of industrial and marine gears(Ref. 1,2).

The effort described in this paper addresses a desire in the gear industry to increase power densities and reduce costs of geared transmissions. To achieve these objectives, new materials and manufacturing processes, utilized in the fabrication of gears, and being evaluated. In this effort, the first priority is to compare the performance of gears fabricated using current materials and processes. However, once that priority is satisfied, it rapidly transforms to requiring accurate design data to utilize these novel materials and processes. This paper describes the effort to address one aspect of this design data requirement.

There are numerous engineering evaluations required to design gear sets for optimum performance with regard to torque capacity, noise, size and cost. How much cost savings and added gear performance is available through optimization? Cost savings of 10% to 30% and 100% added capacity are not unusual. The contrast is more pronounced if the original design was prone to failure and not fit for function.

Effective gear designs balance strength, durability, reliability, size, weight, and cost. Even effective designs, however, can have the possibility of gear cracks due to fatigue. In addition, truly robust designs consider not only crack initiation, but also crack propagation trajectories. As an example, crack trajectories that propagate through the gear tooth are the preferred mode of failure compared to propagation through the gear rim. Rim failure will lead to catastrophic events and should be avoided. Analysis tools that predict crack propagation paths can be a valuable aid to the designer to prevent such catastrophic failures.

I've been thinking a lot about the importance of manufacturing over the last couple of years, especially as I've watched more and more of it leave our country. We work in an industry that is both economically and strategically vital, but I'm concerned that most Americans do not realize the importance of manufacturing, or what will happen if it continues to dissipate.

The author has written this book primarily from the viewpoint of analyzing vibrations on heavy industrial and mill gearing that may have been in service for a prolonged time. The purpose is to diagnose problems, especially the source or cause of failure. However, the principles and analysis techniques can be used for all types and sizes of gears, as well as for gear noise analysis.

Plastics as gear materials represent an interesting development for gearing because they offer high strength-to-weight ratios, ease of manufacture and excellent tribological properties (Refs. 1-7). In particular, there is a sound prospect that plastic gears can be applied for power transmission of up to 10 kW (Ref. 6).

This article describes a method and a computer program that were developed for 3-D finite element analysis of long-fiber reinforced composite spur gears, in which long fibers are arranged along tooth profiles. For such a structure, the gear is composed of two regions; namely the long fiber reinforced and the chopped-fiber reinforced regions.

A good sailor can predict when the weather is about to change. He uses simple tools to measure variables like air pressure, temperature and wind speed. Although those indicators can't perfectly forecast the weather, the sailor can get a good idea of what's going to happen by applying his experience, judgment and even his gut feelings.

In recent years, improvements in the reliability of the vacuum carburizing process have allowed its benefits to be realized in high-volume, critical component manufacturing operations. The result: parts with enhanced hardness and mechanical properties.

an advancing technology and higher energy costs appear to be leading heat-treating companies in the gear industry toward cleaner, more energy-efficient processes. These processes may offer some relief to heat treaters through cooler factories and some relief to their companies through reduced energy usage.

Transmission errors, axial shuttling forces and friction result in bearing forces that serve as the major excitations of gear noise. This paper will use these factors as well as gear stresses and tribological factors to assist in obtaining optimal gear designs.

Optimizing the running behavior of bevel and hypoid gears means improving both noise behavior and load carrying capacity. Since load deflections change the relative position of pinion and ring gear, the position of the contact pattern will depend on the torque. Different contact positions require local 3-D flank form optimizations for improving a gear set.

Gearbox performance, reliability, total cost of ownership (energy cost), overall impact on the environment, and anticipation of additional future regulations are top-of-mind issues in the industry. Optimization of the bearing set can significantly improve gearbox performance.

When, in 1980, OSU professor Donald R. Houser created the Gear and Power Transmission Research Laboratory - then known as the Gear Dynamics and Gear and Power Transmission Laboratory (GearLab) - he did so with the seed money provided
by just three companies. Thirty-three years out, the lab has continued to grow, impress and—most importantly - succeed; it now boasts a roster of some 50 sponsoring companies and government agencies.

Big gears, They drive the machinery that rolls steel, grinds limestone, pulverizes coal, pumps mud, mixes rubber, raises bridges and does many other heavy-duty industrial jobs. For 117 years, big gears have also driven the business of Horsburgh & Scott of Cleveland, OH.

In the last couple of years, many research projects dealt with the determination of load limits of cylindrical worm gears. These projects primarily focused on the load capacity of the worm wheel, whereas the worm was neglected. This contribution presents investigations regarding damages such as large scores and cracks on the flanks of case-hardened worms.

In order to increase the load carrying capacity of hardened gears, the distortion of gear teeth caused by quenching must be removed by precision cutting (skiving) and/or grinding. In the case of large gears with large modules, skiving by a carbide hob is more economical than grinding when the highest accuracy is not required.

Economic production is one of the main concerns of any manufacturing facility. In recent years, cost increases and tougher statutory requirements have increasingly made cutting fluids a problematic manufacturing and cost factor in metalworking. Depending on the cutting fluid, production process and supply unit, cutting-fluid costs may account for up to 16% of workpiece cost. In some cases, they exceed tool cost by many times (Ref. 1). The response by manufacturers is to demand techniques for dry machining (Ref. 2).

Pride. Awe. Relief. Admiration. These were some of the emotions with which I, like most Americans, greeted the end of the Persian Gulf War. I was proud of our country for saying it would do a job and then doing it with a minimum of loss and a maximum of effectiveness; I was awed by the terrifying efficiency of our weapons and relieved that our casualties were so light; and I was filled with admiration at the skill with which one of the most complex logistical military operations of the century was carried out.

A main limiting factor in extending the use of hard coatings to machine component application is the lack of knowledge about how these inert coatings perform under lubricated conditions using today's lubricants.

The United States’ long-held dream of energy independence—as in cheap, clean, free of overseas extortion and renewable energy—could very well be realized in part by the country-wide development of wind turbines...

Aerospace manufacturing has seen quite a turnaround in the past few years. The world's manufacturers of airplanes, helicopters, missiles, space vehicles and satellites are all extremely busy right now--and that's keeping quite a few gear manufacturers busy as well.

Getting rid of personal mementos is an arduous housekeeping ritual for some
of us; every last gear has a memory. One man’s trash is another man’s gold, after all, or in some cases, one failed business is a forgotten piece of personal and mechanical genealogy. Such is the case of the Hill-Climber chainless bicycle, the remains of which were pulled from a family junk pile after nearly half a century.

The global wind energy market has seen average growth rates of 28 percent over the last 10 years, according to the Global Wind Energy Council (GWEC), creating major challenges for the component supply industry. GWEC also forecasts an average growth rate of 22 percent for the next five years, which if realized, will continue to put pressure on suppliers of turbine components.

This presentation is an expansion of a previous study (Ref.1) by the authors
on lapping effects on surface finish and transmission errors. It documents
the effects of the superfinishing process on hypoid gears, surface finish and transmission errors.

In this paper, a method is presented for analyzing and documenting the pitting failure of spur and helical gears through digital photography and automatic computerized evaluation of the damaged tooth fl ank surface. The authors have developed an accurate,
cost-effective testing procedure that provides an alternative to vibration analysis or oil debris methods commonly used in conjunction with similar test-rig programs.

Induction hardening is a heat treating technique that can be used to selectively harden portions of a gear, such as the flanks, roots and tips of teeth, providing improved hardness, wear resistance, and contact fatigue strength without affecting the metallurgy of the core and other parts of the component that don’t require change. This article provides an overview of the process and special
considerations for heat treating gears. Part I covers gear materials, desired microsctructure, coil design and tooth-by-tooth induction hardening.

Before retiring from St. Louis Gear in 2000, Roy Harmon liked to tinker. Since
the customer base at the time was seasonal, Harmon was looking for a project to keep himself busy. The engineer decided to challenge himself
by designing a “South Pointing Chariot,” a device he had read about in the book The Evolution of the Gear
Art by Darle Dudley.

What’s that sound? The churning of gear teeth meshing with the creak of film reels. A bit of “Holmesian deduction” leads us to the conclusion that it’s time for the next installment of the Addendum’s Gears in Film Series!

As the automotive industry continues to reinvent itself, new transmission
technologies are at the forefront of this effort, and there is a whirlwind
of new developments being detailed at the German Car Training Institute’s
Automotive Transmissions and Drive
Trains Symposium North America.

It’s happened to most manufacturers at one point or another. A defective
product comes back from a customer in
need of repair. Perhaps a bearing or a
gear drive has failed, and the customer
simply needs a replacement. Upon further
examination, the company realizes it was never one of its products in the
first place, but a fabricated copy that
snuck into the market. The manufacturing
community has been dealing with
counterfeit products for decades, but
used machinery dealers and Internet
shoppers seem to continuously get hit
by scam artists.

An experimental effort has been conducted on an aerospace-quality helical gear train to investigate the thermal behavior of the gear system. Test results from the parametric studies and the superfinishing process are presented.

Conical involute gears, also known as beveloid gears, are generalized involute gears that have the two flanks of the same tooth characterized by different base cylinder radii and
different base helix angles.

I recently attended a briefing, arranged by the White House, regarding the Treasury's tax simplification plan. A
Treasury Undersecretary explained that their goal was to come up with a tax code that was "fair" to everyone.

No matter how well gears are designed and manufactured, gear corrosion can occur that may easily result in catastrophic failure. Since corrosion is a sporadic and rare event and often difficult to observe in the root fillet region or in finely pitched gears with normal visual inspection, it may easily go undetected. This paper
presents the results of an incident
that occurred in a gear manufacturing
facility several years ago that resulted in pitting corrosion and intergranular attack (IGA).

Chicago has been known as many things over the years—“Hog Butcher to the World,” “The City That Works,” “The Windy City” and “The City of Big Shoulders” among them. Although perhaps lesser known, add “City of Bridges” to the list.

Today, because of reduced cost of coatings and quicker turnaround times, the idea of all-around coating on three-face-sharpened blades is again economically viable, allowing manufacturers greater freedoms in cutting blade parameters, including three-face-sharpened and even four-face-sharpened blades.

Instances of damage to discontinuous form ground and surface-hardened gears, especially of large scale, have recently increased. This may be attributed partly to a faulty grinding process with negative effects on the surface zones and the surface
properties.

Never have so few served so many. That, in essence, describes gear makers
and the role they play in our world.
Think of it—although the gear cutting
industry represents much less than one
percent of the global workforce—the
gears it produces are what make things
run in practically every industry and
profession imaginable. From bulldozers
to Rolexes, gears are an integral part of the mix.

The use of plastic gearing is increasing steadily in new products.
This is due in part to the availability of recent design data. Fatigue
stress of plastic gears as a function of diametral pitch, pressure angle,
pitch line velocity, lubrication and life cycles are described based
on test information. Design procedures for plastic gears are presented.

The manufacturing quality of spiral bevel gears has achieved a very high standard. Nevertheless, the understanding of the real stress conditions and the influences. of certain parameters is not satisfactory.

Calculation of gear tooth flexibility is of interest for at least two reasons: (a) It controls, at least in part, the vibratory properties of a transmission system hence, fatigue resistance and noise: (b) it controls load sharing in multiple tooth contact.

Advancements in machining and assembly techniques of thermoplastic gearing along with new design data has lead to increased useage of polymeric materials. information on state of the art methods in fabrication of plastic gearing is presented and the importance
of a proper backlash allowance at installation is discussed. Under controlled conditions, cast nylon gears show 8-14 dBA. lower noise level than three other gear materials tested.

Part I, which was published in the September/October 2008 issue, covered gear materials, desired microstructure, coil design and tooth-by-tooth induction hardening. Part II covers spin hardening and various heating concepts used with it.

Since the design of involute splines and
their manufacture requires considerable
knowledge, not only of the basic properties of the involute profile, but also of various other elements which affect the spline fit and the sometimes complex principles underlying manufacturing and checking equipment, the question is frequently raised as to why the involute profile is given preference in designing splines over the seemingly simpler straight sided tooth profile.

Since our founding in 1984, Gear Technology’s goal has been to educate and inform our readers of the technologies, products, processes,
services and news of importance to the gear industry and to provide our advertisers with the most complete and current circulation of gear
industry professionals available anywhere!

This article summarizes the use of laboratory fatigue data for bearings and gears coupled with probabilistic life prediction and EHD theories to predict the life and reliability of a commercial turboprop gearbox.

A single tooth bending (STB) test procedure has been developed to optimally map gear design parameters. Also, a test program on case-carburized, aerospace standard gears has been conceived and performed in order to appreciate the influence of various technological parameters on fatigue resistance and to draw the curve shape up to the gigacycle
region.

The greenlighting of new product designs specifying micro-sized, plastic gear sets is often dependent upon existing technology and a company’s capabilities to manufacture those gears, and to do so cost-effectively

When children are asked what they want to be when they grow up, the answers are undoubtedly diverse. Some immediately respond with doctor, lawyer
or firefighter while others take a more creative approach with answers
like spy, princess or superhero. The
Addendum Staff has yet to come across
a youngster that seems committed to a
career in gear manufacturing.

The Pentac Plus is the latest generation of Gleason’s Pentac bevel gear cutting system. It is designed to allow much higher tool life and improved productivity, especially for cutters using multiple face blade geometry.

Nondestructive examination (NDE) of ferrous and nonferrous materials has long proved an effective maintenance and anomaly characterization tool for many industries. Recent research has expanded its applicability to include the inspection of large, open gear drives. Difficulties inherent in other NDE methods make them time-consuming and labor-intensive. They also present the user with the environmental problem of the disposal of used oil. The eddy current method addresses these problems.

There are great advantages in dry hobbing, not only for friendliness
toward the environment, but also for increasing productivity and for decreasing manufacturing cost. Dry hobbing, however, often causes failures in hob cutting edges or problems with the surface quality of gear tooth flanks. These difficulties are not present when hobbing with cutting oil. Pinching and crushing of generated chips between the hob cutting edge and the work gear tooth flank is considered a major cause of those problems.

On a highway, a compact pick-up truck struggles to tow a 30-foot boat up a steep grade. Inside the pick-up, the owner curses himself. He saved money leasing a smaller truck but sees now that he really needed a bigger, pricier vehicle, one suitable for this job.

If a gear system is run continuously for long periods of time—or if the starting loads are very low and within the normal operating spectrum—the effect of the start-up conditions may often be insignificant in the determination of the life of the gear system. Conversely, if the starting load is significantly higher than any of the normal operating conditions,
and the gear system is started and stopped frequently, the start-up load may, depending on its magnitude and frequency, actually be the overriding, limiting design condition.

Excess lubricant supply in gearing contributes to power loss due to churning as well as the requirements of the lubrication system itself. Normally, a much larger amount of oil than required is used for cooling because so much of it is thrown away by centrifugal force. To lower the amount of lubricant required and
reduce those losses, it is necessary to discover the ideal location of the supplying nozzle.

Often, the required hardness qualities of parts manufactured from steel can only be obtained through suitable heat
treatment. In transmission manufacturing, the case hardening process is commonly used to produce parts with a hard and wear-resistant surface and an adequate toughness in the core. A tremendous potential for rationalization, which is only
partially used, becomes available if the treatment time of the case hardening process is reduced. Low pressure carburizing (LPC) offers a reduction of treatment time in comparison to conventional gas carburizing because of the high carbon
mass flow inherent to the process (Ref. 1).

Where were you? We were hoping to see you here at Gear Expo. We were surprised that you didn't make it.
Anyway, we had a really good show, along with more than a hundred other leading companies in the gear industry
who exhibited this year.

Bevel gears have been the standard for several decades in situations where power transmission has to occur between shafts mounted at a given angle. Now a new approach has been developed that challenges the bevel gear's de facto monopoly in such applications. The concept is based on the principle of the crown gear; i.e., a cylindrical pinion mates with a face gear. Crown Gear B.V. in Enschede, Holland, is the developer of these specialty gear teeth, which are marketed under the trade name Cylkro.

The word gear, in various forms, has been in use since around A.D. 1200, according to the Oxford English Dictionary. Last issue we brought you Shakespearean gears. Now we'd like to show you some of the uses Americans have given our favorite word (from the Random House Dictionary of American Slang).

Hobbing is a continuous gear generation process widely used in the industry for high or low volume production of external cylindrical gears. Depending on the tooth size, gears and splines are hobbed in a single pass or in a two-pass cycle consisting of a roughing cut followed by a finishing cut. State-of-the-art hobbing machines have the capability to vary cutting parameters between first and second cut so that a different formula is used to calculate cycle times for single-cut and double-cut hobbing.

In the lubrication and cooling of gear teeth a variety of oil jet lubrication schemes is sometimes used. A method commonly used is a low pressure, low velocity oil jet directed at the ingoing mesh of the gears, as was analyzed in Reference 1. Sometimes an oil jet is directed at the outgoing mesh at low pressures. It was shown in Reference 2 that the out-of-mesh lubrication method provides a minimal impingement depth and low cooling of the gears because of the short fling-off time and fling-off angle.(3) In References 4 and 5 it was shown that a radially directed oil jet near the out-of-mesh position with the right oil pressure was the method that provided the best impingement depth.

Graded hardening technology has proven over the years to yield very good results when used in the heat treating of carburized gears. It is especially advantageous for smaller companies, subject to higher competitive pressures. Unfortunately, despite the fact that graded hardening is a very well-known method, its use has been limited. We strongly recommend this technology to all of those who need to produce gears with high metallurgical quality.

This article deals with certain item to be taken into consideration for gear grinding, common problems that arise in gear grinding and their solutions. The discussion will be limited to jobbing or low-batch production environments, where experimental setup and testing is not possible for economic and other reasons.

An engineer's responsibility for verifying a new design or product concept as manufacturable early in the development cycle is a tough challenge. What appears to work on a blueprint or in a three-dimensional CAD file on a computer screen many not work on the factory floor; and the downstream impact on the manufacturing process of an undetected design flaw can be enormous. Costs can run into the millions.

The popular perception today is that technological advancement is an engine running almost out of control. New products and processes are developing faster than we can keep up with them, as anyone who has had a new computer system crash into obsolescence practically before it's out of the box can tell you. But that's not the case everywhere. Transmission technology, for example.

One of the most frequently neglected areas of gear design is the determination of "form diameter". Form diameter is that diameter which specifies the transition point between the usable involute profile and the fillet of the tooth. Defining this point is important to prevent interference with the tip of the mating gear teeth and to enable proper preshave machining when the gear is to be finished with a shaving operation.

A gear shaper cutter is actually a gear with relieved cutting edges and increased addendum for providing clearance in the root of the gear being cut. The maximum outside diameter of such a cutter is limited to the diameter at which the teeth become pointed. The minimum diameter occurs when the outside diameter of the cutter and the base circle are the same. Those theoretical extremes, coupled with the side clearance, which is normally 2 degrees for coarse pitch cutters an d1.5 degrees for cutters approximately 24-pitch and finer, will determine the theoretical face width of a cutter.

How dynamic load affects the pitting fatigue life of external spur gears was predicted by using NASA computer program TELSGE. TELSGE was modified to include an improved gear tooth stiffness model, a stiffness-dynamic load iteration scheme and a pitting-fatigue-life prediction analysis for a gear mesh. The analysis used the NASA gear life model developed by Coy, methods of probability and statistics and gear tooth dynamic loads to predict life. In general, gear life predictions based on dynamic loads differed significantly from those based on static loads, with the predictions being strongly influenced by the maximum dynamic load during contact.

Why Brushes?
In this age of hi-tech, robots, automatic machines, machining cells, etc., is there a niche somewhere for power brushes? Let me answer by asking another question. What tool does the gear manufacturer have in his arsenal that allows him to deburr green gears, hardened gears, hobbed gears, ground gears and shaved gears? What tool allows him to deburr powder metal gears - green and sintered - brass gears, bronze gears, stainless gears made of exotic materials such as inconel, waspaloy, or hastaloy, and fiber and plastic gears? How about spur gears, helical gears, sprockets, both internal and external splines, clutch teeth and pump gears?

This article describes a method of obtaining gear tooth profiles from the geometry of the rack (or hob) that is used to generate the gear. This method works for arbitrary rack geometries, including the case when only a numerical description of the rack is available. Examples of a simple rack, rack with protuberances and a hob with root chamfer are described. The application of this technique to the generation of boundary element meshes for gear tooth strength calculation and the generation of finite element models for the frictional contact analysis of gear pairs is also described.

Recent history has taught us that global competition has become tougher and is a major concern of American gear manufacturers from abroad have invaded American markets with products designed in an environment where management of technology has been practiced effectively. If American companies intend to compete in the changing world market, they must acquire the technologies that will allow them to do so.

The south-pointing chariot exhibited at the Smithsonian Institution, Washington, D.C., (circa 2600 BC)is shown in Fig. 1. Although the mechanism is ancient, it is by no means either primitive or simplistic. The pin-tooth gears drive a complex system, wherein the monk on the top of the chariot continues to point in a preset direction, no matter what direction the vehicle in moved, without a slip of the wheels.(1)

Back in the days when our great, great, great, etc., grandaddies were designing gears, one of the most common materials in use was wood. For fairly obvious reasons, we don't see too many wooden gears around anymore. But there are a few.

Several methods of oil jet lubrication of gears are practiced by the gear industry. These include the oil jet directed into the mesh, out of the mesh and radially directed into the gear teeth. In most cases an exact analysis is not used to determine the optimum condition such as, jet nozzle location, direction and oil jet velocity, for best cooling. As a result many gear sets are operating without optimum oil jet lubrication and cooling.

For many years chromium has been a popular alloy for heat treatable steels because of its contribution to hardenability more than offsets its costs. As a consequence, it is specified in such high-tonnage steel grades as the 5100, 4100, and 8600 series; and, as a result, about 15% of the annual U.S. consumption of chromium is used in constructional alloy steels.

The type of lubricant and the method of applying it to the tooth flanks of large open gears is very important from the point of view of lubrication technology and maintenance. When selecting the type of lubricant and the application method, it is important to check whether it is possible to feed the required lubricant quantity to the load-carrying tooth flanks, This is necessary to avoid deficient lubrication, damage to the gear and operational malfunctions. It is important to determine the type of lubricant, which may be fluid or grease-like. The consistency of the lubricant will have a direct impact on the ability of the lubrication system to feed adequately the lubricant to the gear. The interactions between the common types of lubricant and the lubrication application methods for open gear drives are shown in Fig. 1.

Electroless Nickel (EN) plating, a process dating back to the 1940s, is one of the predominant metal finishing methods today. It is especially suitable for the gear industry, whose end uses span innumerable other industries, providing an endless assortment of requirements, environments, materials and specifications. EN plating has a broad array of functional features, which include:

Aircraft transmissions for helicopters, turboprops and geared turbofan aircraft require high reliability and provide several thousand hours of operation between overhauls. In addition, They should be lightweight and have very high efficiency to minimize operating costs for the aircraft.

Plastic gears are being used increasingly in applications, such as printers, cameras, small household appliances, small power tools, instruments, timers, counters and various other products. Because of the many variables involved, an engineer who designs gear trains on an occasional basis may find the design process to be somewhat overwhelming. This article outlines a systematic design approach for developing injection molded plastic spur and helical gears. The use of a computer program for designing plastic gears is introduced as an invaluable design tool for solving complex gearing equations.

It's a buyer's market these days on solutions for our country's economic problems. Everybody with access to a t.v. camera or a publisher is telling us what we need to do. Usually their solution involves either buying their book or tape or electing them to office.

In the 1960's and early 1970's, considerable work was done to identify the various modes of damage that ended the lives of rolling element bearings. A simple summary of all the damage modes that could lead to failure is given in Table 1. In bearing applications that have insufficient or improper lubricant, or have contaminants (water, solid particles) or poor sealing, failure, such as excessive wear or vibration or corrosion, may occur, rather than contact fatigue. Usually other components in the overall system besides bearings also suffer. Over the years, builders of transmissions, axles, and gear boxes that comprise such systems have understood the need to improve the operating environment within such units, so that some system life improvements have taken place.

A common goal of gear manufacturers is to produce gearing that is competitively priced, that meets all quality requirements with the minimum amount of cost in a timely manner, and that satisfies customers' expectations.
In order to optimize this goal, the gear manufacturer must thoroughly understand each manufacturing process specified, the performance capability of that process, and the effect of that particular process as it relates to the quality of the manufactured gear. If the wrong series of processes has been selected or a specific selected process is not capable of producing a quality part, manufacturing costs are greatly increased.

Following is the second part of an article begun in our last issue. The first part covered basic shot peening theory, shot peening controls, and considerations that should go into developing a shot peening specification. Part II covers optional peening methods and the relationship of shot peening specifications to the drawings.

Shot peening is widely recognized as a prove, cost-effective process to enhance the fatigue characteristics of metal parts and eliminate the problems of stress corrosion cracking. Additional benefits accrue in the areas of forming and texturizing. Though shot peening is widely used today, the means of specifying process parameters and controlling documents for process control are not widely understood. Questions regarding shot size, intensity, and blueprint specification to assure a high quality and repeatable shot peening process are continually asked by many design and materials engineers.
This article should answer many of the questions frequently asked by engineering professionals and to further assist companies interested in establishing a general shot peening specification.

Columbus' first voyage to the Americas is not the only anniversary worthy of celebration this year. In 1892, on October 15, Wilfred Lewis gave an address to the Engineer's Club of Philadelphia, whose significance, while not as great as that of Columbus' voyage, had important results for the gearing community. In this address, Lewis first publicly outlined his formula for computing bending stress in gear teeth, a formula still in use today.

The advent of CNC technology as applied to gear shaping machines has, in the last 10 years, led to an astonishing improvement in both productivity and quality. As is usual when developments such as this take place, the technology of the machine tool suddenly jumps ahead of that of the cutting tool, and the machine is then capable of producing faster than the cutting tool can withstand.

The complete and accurate solution t the contact problem of three-dimensional gears has been, for the past several decades, one of the more sought after, albeit elusive goals in the engineering community. Even the arrival on the scene in the mid-seventies of finite element techniques failed to produce the solution to any but the most simple gear contact problems.

Gear Expo '93 - another trade show, another plea to send people and/or equipment out of town, away from the office or plant. Another bid to spend time, money, and effort. Oh, please! Hasn't anybody heard that these are the "lean and mean" '90s?

ISO 9000 is the latest hot topic in marketing and manufacturing circles. Everyone seems to be talking about it, but few seem to understand it completely. depending on whom one talks to, it's either the greatest thing to hit industry since the assembly line, another cash cow for slick consultants, a conspiracy on the part of Europeans to dominate global markets, or the next necessary step to compete in the global economy of the twenty-first century. It may be all of the above.

"God is in the details," says the philosopher. What he meant was that on the scale of the universe, it's not just the galaxies, the planets, the mountain ranges, or the major rivers that are important. So are the subatomic particles and the genes. It's the little things that make all the difference.

The quality of gearing is a function of many factors ranging from design, manufacturing processes, machine capability, gear steel material, the machine operator, and the quality control methods employed. This article discusses many of the bevel gear manufacturing problems encountered by gear manufacturers and some of the troubleshooting techniques used.

The merits of CBN physical characteristics over conventional aluminum oxide abrasives in grinding performance are reviewed. Improved surface integrity and consistency in drive train products can be achieved by the high removal rate of the CBN grinding process. The influence of CBN wheel surface conditioning procedure on grinding performance is also discussed.

The passage last year of both NAFTA and GATT has gone a long way toward leveling the playing field for American manufacturers and other hoping to compete in the global economy. Add to this news the fact that the domestic economy keeps growing, and it seems as though good times are ahead for the gear industry.

A research program, conducted in conjunction with a U.S. Army contract, has resulted in the development of manufacturing technology to produce a multi-metal composite gear/shaft representing a substantial weight savings compared to a solid steel component. Inertia welding is used to join a steel outer ring to a light-weight titanium alloy web and/or shaft through the use of a suitable interlayer material such as aluminum.

Heat Treating - The evil twin of the gear processing family. Heat treating and post-heat treating corrective processes can run up to 50% or more of the total gear manufacturing cost, so it's easy to see why, in these days when "lean and mean" production is the rage, and every part of the manufacturing process is under intense scrutiny, some of the harshest light falls on heat treating.

Gear shaping is one of the most popular production choices in gear manufacturing. While the gear shaping process is really the most versatile of all the gear manufacturing methods and can cut a wide variety of gears, certain types of gears can only be cut by this process. These are gears closely adjacent to shoulders; gears adjacent to other gears, such as on countershafts; internal gears, either open or blind ended; crown or face gears; herringbone gears of the solid configuration of with a small center groove; rack; parts with filled-in spaces or teeth, such as are used in some clutches.

This article discusses an application driven approach to the computer-aided sizing of spur gear teeth. The methodology is bases on the index of tooth loading and environment of application of the gear. It employs handbook knowledge and empirical information to facilitate the design process for a novice. Results show that the approach is in agreement with the textbook data. However, this technique requires less expert knowledge to arrive at the conclusion. The methodology has been successfully implemented as a gear tooth sizing module of a parallel axis gear drive expert system.

Cubic boron nitride (CBN) finishing of carburized gearing has been shown to have certain economic and geometric advantages and, as a result, it has been applied to a wide variety of precision gears in many different applications.
In critical applications such as aerospace drive systems, however, any new process must be carefully evaluated before it is used in a production application. Because of the advantages associated with this process, a test program was instituted to evaluate the load capacity of aerospace-quality gears finished by the CBN process as compared to geometrically identical gears finished by conventional grinding processes.
This article presents a brief description of the CBN process, its advantages in an aerospace application, and the results of an extensive test program conducted by Boeing Helicopters (BH) aimed at an evaluation of the effects of this process on the scoring, surface durability, and bending fatigue properties of spur gears.
In addition, the results of an x-ray diffraction study to determine the surface and subsurface residual stress distributions of both shot-peened and nonshot-peened CBN-ground gears as compared to similar conventionally ground gears are also presented.

Gear design has long been a "black art." The gear shop's modern alchemists often have to solve problems with a combination of knowledge, experience and luck. In many cases, trial and error are the only effective way to design gears. While years of experience have produced standard gearsets that work well for most situations, today's requirements for quieter, more accurate and more durable gears often force manufacturers to look for alternative designs.

Traditional methods of manufacturing precision gears usually employ either hobbing or shaper cutting. Both of these processes rely upon generating the conjugate tooth form by moving the work-piece in a precise relation to the tool. Recently, attention has been given to forming gear teeth in a single step. Advantages to such a process include reduced production time, material savings, and improved performance characteristics. Drawbacks include complicated tool designs, non-uniformity of gears produced throughout the life of the tooling, and lengthy development times.

This article presents an efficient and direct method for the synthesis of compound planetary differential gear trains for the generation of specified multiple speed ratios. It is a train-value method that utilizes the train values of the integrated train components of the systems to form design equations which are solved for the tooth numbers of the gears, the number of mating gear sets and the number of external contacts in the system. Application examples, including vehicle differential transmission units, rear-end differentials with unit and fractional speed ratios, multi-input functions generators and robot wrist joints are given.

Cutter Sharpening
Cutter sharpening is very important both during manufacturing and subsequently in resharpening after dulling. Not only does this process affect cutter "over cutting edge" quality and the quality of the part cut, but it can also affect the manner in which chip flow takes place on the cutter face if the surface finished is too rough or rippled.

Getting and keeping a work force capable of meeting the demands of the 21st century is one of the key challenges most U.S. manufacturers face today. That's not even news anymore. I - and others - have been talking about it in editorials and speeches for ten years now. It's also not news that the job is a tough one and that industry-wide response often has not been particularly effective.

Computer programs have been developed to completely design spur and helical gear shaper cutters starting from the specifications of the gear to be cut and the type of gear shaper to be used. The programs generate the working drawing of the cutter and, through the use of a precision plotter, generate enlarge scaled layouts of the gear as produced by the cutter and any other layouts needed for its manufacture.

This book is written for those among us, with or without a technical background, who have an occasional need to use, purchase or specify gears. The author assumes an audience that is not made up of experienced gear designers, but of people who do need to have a basic understanding of the criteria used by the designer. The subjects covered include not only the gears themselves, but their manufacturing methods, the systems that contain them and the terms used to describe them.

This article provides an overview of the benefits of using psychoacoustic characteristics for describing gear
noise. And with that, human hearing and the most important psychoacoustic values are introduced. Finally, results
of noise tests with different gear sets aree presented. The tests are the basis for a correlation analysis between psychoacoustic values and gear characteristics.

In India, “namaste” is used as a common greeting. Although it translates
literally to “I bow to you,” it’s often
used the same way we use “hello” or
“good-bye.” It’s a phrase commonly
exchanged between individuals when they meet, and it’s also used as a salutation when they part. I’m using the
phrase here because I’d like to introduce you to an exciting new project
and venture for Randall Publications LLC.

In the majority of spiral bevel gears, spherical crowning is used. The contact pattern is set to the center of the active tooth flank and the extent of the crowning is determined by experience. Feedback from service, as well as from full-torque bench tests of complete gear drives, has shown that this conventional design practice leads to loaded contact patterns, which are rarely optimal in location and extent. Oversized reliefs lead to small contact area, increased stresses and noise, whereas undersized reliefs result in an overly sensitive tooth contact.

Hypoid gears are the paragon of gearing. To establish line contact between the pitches in hypoid gears, the kinematically correct pitch surfaces have to be determined based on
the axoids. In cylindrical and bevel gears, the axoids are identical to the pitch surfaces and their diameter or cone angle can be calculated simply by using the knowledge about number of teeth and module or ratio and shaft angle. In hypoid gears, a rather complex approach is required to find the location of the teeth—even before any information about flank form can
be considered. This article is part seven of an eight-part series on the tribology aspects of angular gear drives.

Throughout the history of civilization attempts have been made to limit the number of the measuring systems in use with the result that today only two systems, English and metric, are practiced in the industrial nations. Globally, the metric system has been gaining ground, and the English system has been losing it. As of 1986, only the United States, Burma and Brunei remain uncommitted to metric conversion in the sense that no government controlled deadlines for the conversion have been established.

Gear flank breakage can be observed on edge zone-hardened gears. It occurs, for example, on bevel gears for water turbines, on spur gears for wind energy converters and on single- and double-helical gears for other industrial
applications.

I came back from Gear Expo in a pretty good mood, and judging by the smiles on the faces of exhibitors I saw, I'm not alone. In fact, the mood at Gear Expo 2011 was the best I've seen in recent memory.

This article describes some of the most important tests for prototypes conducted at Winergy AG during the product development process. It will demonstrate that the measurement results on the test rig for load distribution are in accordance with the turbine measurements.

The objective of this study was to investigate the limits concerning possible reduction of lubricant quantity in gears that could be tolerated without detrimental effects on their load carrying capacity.

In co-operation with Voith, a major transmission manufacturer in Germany, Heller has developed a process that significantly enhances the productivity of pre-milling and gear milling operations performed on a single 5-axis machining center.

Involute spline couplings are used to transmit torque from a shaft to a gear hub or other rotating component.
External gear teeth on the shaft engage an equal number of internal teeth in the hub. Because multiple teeth engage
simultaneously, they can transmit much larger torques than a simple key and keyway assembly. However, manufacturing
variations affect the clearance between each pair of mating teeth, resulting in only partial engagement.

This paper deals with analysis of the load sharing percentage between teeth in mesh for different load conditions
throughout the profile for both sun and planet gears of normal and HCR gearing—using finite element analysis.
(FEA).

We recently e-mailed an informal survey to 1,000 of our most loyal readers, each of whom has been a subscriber for at least 15 years. We were hoping to hear that our magazine is just as
important to them today as it was when they first signed up. It was gratifying to find out that with most of the respondents, that was the case.

This article is part five of an eight-part series on the tribology aspects of angular gear drives. Each article will be presented first and exclusively by Gear Technology, but the entire series will be included in Dr. Stadtfeld’s upcoming book on the subject, which is scheduled for release in 2011.

Faithful Gear Technology readers may recall that our July 2009 issue contained an update of the deliberations
provided by Bill Bradley. Now, almost two years later, there is an ISO/IEC wind turbine gearbox standard out for draft international standard ballot (ballot closes 2011-05-17).

Zerol bevel gears are the special case of spiral bevel gears with a spiral angle of 0°. They are manufactured in a single-indexing face milling process with large cutter diameters, an extra deep tooth profile and tapered tooth depth.

This paper seeks to compare the data generated from test rig shaft encoders and torque transducers when using steel-steel, steel-plastic and plastic-plastic gear combinations in order to understand the differences in performance of steel and plastic gears.

The large gears found in mining, steel, construction, off-road, marine and energy applications—massive and
robust in nature—need to tackle the greatest production demands. This, in turn, means that a special emphasis must be put on the heat treating methods used to increase the wear resistance and strength properties of gears this size.

THANK YOU! The response to our first issue
has been extremely exciting for us. Our advertisers have told us GEAR TECHNOLOGY is being talked about wherever they go. Thank you for the wonderful and enthusiastic reception.

The search for greater gear life involves improvement in cost, weight and increased power output. There are many events that affect gear life, and this paper addresses those relating to fatigue, gear tooth pitting, fatigue strength losses due to the heat treating processes and shot peening technique. The capability of shot peening to increase fatigue strength and surface fatigue life eliminate machine marks which cause stress risers, and to aid in lubrication when properly controlled, suggests increased use and acceptance of the process.

Crossed helical gear sets are used to transmit power and motion between non-intersecting and non-parallel axes. Both of the gears that mesh with each other are involute helical gears, and a point contact is made between them. They can stand a small change in the center distance and the shaft angle without any impairment in the accuracy of transmitting motion.

NC and CNC metal cutting machines are among the most popular machine tools in the business today, There is also a strong trend toward using flexible
machining centers and flexible manufacturing systems. The same trend is apparent in gear cutting. Currently the trend toward CNC tools has increased, and sophisticated controls and peripheral equipment for gear cutting machines are now available; however, the investment in a CNC gear machine has to be justified on the basis of economic facts as well as technical advantages.

The power of high speed gears for use in the petrochemical industry and power stations is always increasing. Today gears with ratings of up to 70,000kW are already in service. For such gears, the failure mode of scoring can become the limiting constraint. The validity of an analytical method to predict scoring resistance is, therefore, becoming increasingly important.

In conventional gear grinders, grinding wheels with Alundum grains and a hardness of about 2000 HV have been used for finishing steel gears with hardnesses up to about 1000HV. In this case, the accuracy of the gears ground is greatly affected by wear of the grinding wheel because the difference in hardness is comparatively small when the gears are fully hardened.

The forming of gear teeth has traditionally been a time-consuming heavy stock removal operation in which close tooth size, shape, runout and spacing accuracy are required. This is true whether the teeth are finished by a second forming operation or a shaving operation.

In the gearing industry, gears are lubricated and cooled by various methods. At low to moderate speeds and loads, gears may be partly submerged in the lubricant which provides lubrication and cooling by splash lubrication. With splash lubrication, power loss increases considerably with speed. This is partially because of churning losses. It is shown that gear scoring and surface pitting can occur when the gear teeth are not adequately lubricated and cooled.

When a gear set is to be designed for a new application, the minimum size gears with the required capacity are desired. These gears must be capable of meeting the power, speed, ratio, life, and reliability requirements.

With the publishing of various ISO draft standards relating to gear rating procedures, there has been much discussion in technical papers concerning the various load modification factors. One of the most basic of parameters affecting the
rating of gears, namely the endurance limit for either contact or bending stress, has not, however, attracted a great deal of attention.

As the time came to write this editorial, the replies to our survey from the last issue were just starting to pour in. We were gratified by the number of responses we received and by the amount of time many of you spent
answering in great detail the text
questions on the survey. Because of
this unusually large response, it will
take us some months to log, digest
and respond to all the data. Thank
you for this nice "problem."

Selection of the number of teeth for each gear in a gear train such that the output to input angular velocity ratio is a specified value is a problem considered by relatively few published works on gear design.

In ParI 1 several scuffing (scoring) criteria were shown ultimately to converge into one criterion, the original flash temperature criterion according to Blok. In Part 2 it will be shown that all geometric influences may be concentrated in one factor dependent on only four independent parameters, of which the gear ratio, the number of teeth of the pinion, and the addendum modification coefficient of the pinion are significant.

A pair of spur gears generally has an effective lead error which is caused, not only by manufacturing and assembling errors, but also by the deformations of shafts, bearings and housings due to the transmitted load. The longitudinal load distribution on a contact line of the teeth of the gears is not uniform because of the effective lead error.

The last decade has been a period of
far-reaching change for the metal working industry. The effect of higher lubricant costs, technical advances in machine design and increasing competition are making it essential that manufacturers of gears pay more attention to testing, selecting and controlling cutting fluid systems. Lubricant costs are not a large
percentage of the process cost relative to items such as raw materials, equipment and labor, and this small relative cost has tended to reduce the economic incentive to evaluate and to change cutting fluids.

As a result of extensive research into the vibration characteristics of gear drives, a systematic approach has evolved, by which damaging resonances can be eliminated. The method combines
finite element techniques with experimental signature and modal
analyses. Implementation of the bulk of the method can be carried out early in the design stage. A step-by-step description of the approach, as it was applied to an existing accessory drive, is given in the text. It is shown how
premature bearing failures were eliminated by detuning the torsional
oscillations of a gearshaft. A dramatic reduction in vibration levels was achieved as a result of detuning the problem gear. The proposed approach can be extended to other types of rotating machines.

To mechanical engineers, the strength of gear teeth is a question of constant recurrence, and although the problem to be solved is quite elementary in character, probably no other question could be raised upon which such a diversity of opinion exists, and in support of which such an array of rules and authorities might be quoted. In 1879, Mr. John H. Cooper, the author of a well-known work on "Belting," made an examination of the subject and found there were then in existence about forty-eight well-established rules for horsepower and working strength, sanctioned by some twenty-four authorities, and differing from each other in extreme causes of 500%. Since then, a number of new rules have been added, but as no rules have been given which take account of the actual tooth forms in common use, and as no attempt has been made to include in any formula the working stress on the material so that the engineer may see at once upon what assumption a given result is based, I trust I may be pardoned for suggesting that a further investigation is necessary or desirable.

Our company manufactures a range of hardened and ground gears. We are looking into using skiving as part of our finishing process on gears in the 4-12 module range made form 17
CrNiMO6 material and hardened to between 58 and 62 Rc. Can you tell us more about this process?

Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Tests were conducted with VIM-VAR AISI 9210 carburized and hardened gears that were finish ground with either CBN or vitreous grinding methods. Test conditions were an inlet oil temperature of 320 K (116 degree F), an outlet oil temperature of 350 K (170 degree F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. The CBN ground gears exhibited a surface fatigue life that was slightly better than the vitreous ground gears. The subsurface residual stress of the CBN ground gears was approximately the same as that for the standard vitreous ground gears for the CBN grinding method used.

From tiny beginnings, the AGMA Gear Expo is growing into a fine, strapping show. This year's effort, Gear Expo '89, "The Cutting Edge," will be bigger and better than ever. What started as a few tabletop exhibits in Chicago four years ago has now grown to a full-size, international exhibition at the David Lawrence Convention Center in Pittsburgh. With over 160 exhibitors, including major gear manufacturers and suppliers from around the world, this year's show promises to be a great success as well.

The use of dimensionless factors to describe gear tooth geometry seems to have a strong appeal to gear engineers. The stress factors I and J, for instance, are well established in AGMA literature. The use of the rack shift coefficient "x" to describe nonstandard gear proportions is common in Europe, but is not as commonly used in the United States. When it is encountered in the European literature or in the operating manuals for imported machine tools, it can be a source of confusion to the American engineer.

Micropitting, pitting and wear are typical gear failure modes that can occur on the flanks of slowly operated and highly stressed internal gears. However, the calculation methods for the flank load-carrying capacity have mainly been established on the basis of experimental investigations of external gears. This paper describes the design and functionality of the newly developed test rigs for internal gears and shows basic results of the theoretical studies. It furthermore presents basic examples of experimental test results.

Engineering design requires many different types of gears and splines. Although these components are rather expensive, subject to direct wear, and difficult to replace, transmissions with gears and splines are required for two very simple reasons:
1) Motors have an unfavorable (disadvantageous) relation of torque to number of revolutions.
2)Power is usually required to be transmitted along a shaft.

Six years ago this month, the very first issue of Gear Technology, the Journal of Gear Manufacturing, went to press. The reason for starting the publication was a straightforward one: to provide a forum for the presentation of the best technical articles on gear-related subjects from around the world. We wanted to give our readers the information they need to solve specific problems, understanding new technologies, and to be informed about the latest applications in gear design and manufacturing. The premise behind Gear Technology was also a straightforward one: the better informed our readers were about the technology, the more competitive they and their companies would be int he world gear market.

Although typically considered a late bloomer in the call to wind energy arms, the United States is now the
number one wind power producer in the world with over 25,000 MW installed by the end of 2008, according to the Global Wind Energy Council in January 2009.

Many CAD (Computer Aided Design) systems have been developed and implemented to produce a superior quality design and to increase the design productivity in the gear industry. In general, it is true that a major portion of design tasks can be performed by CAD systems currently available. However, they can only address the computational aspects of gear design that typically require decision-making as well. In most industrial gear design practices, the initial design is the critical task that significantly effects the final results. However, the decisions about estimating or changing gear size parameters must be made by a gear design expert.

Who knew what a few hundred bacteria could do with a little cooperation? Andrey Sokolov of Princeton University, Igor Aronson from the Argonne National Laboratory and Bartosz Grzybowski and Mario Apodaca from Northwestern University found out after placing microgears (380 microns long with
slanted spokes) in a solution with the common aerobic bacteria Bacillus subtilis. The scientists observed that the bacteria appeared to swim randomly but occasionally collided with the
spokes of the gears and turned them.

Publisher Michael Goldstein describes the remarkable accomplishments of Randall Publications LLC over the past year, despite the intense and hectic
transformation he and the staff experienced unbelievable strain on their time and concentration.

At Muncie Power, the objective of noise and vibration testing is to develop
effective ways to eliminate power
take-off (PTO) gear rattle, with specific emphasis on PTO products. The
type of sound of largest concern in this
industry is tonal.

India is rapidly turning into a global manufacturing hub, thanks to the country’s manufacturing and engineering
capabilities, vast pool of skilled expertise and its size. These qualities offer it a strategic advantage for the manufacturing segment. A large number of international companies in varied
segments have already set up a manufacturing base in India and others are following suit. It only makes sense to bring this industry segment together under one roof to discuss the current
trends and technology prevalent to the marketplace. IPTEX 2012 is scheduled from February 9–11, 2012 at the Bombay Exhibition Center in Mumbai, India.

In November, Gear Technology conducted
an anonymous survey of gear manufacturers. Invitations were sent by e-mail to thousands of individuals around the world. More than 300
individuals responded to the online survey, answering questions about their manufacturing operations and current challenges facing their businesses.

Since we are a high volume shop, we were particularly interested in Mr. Kotlyar's article describing the effects of hob length on production efficiency which appeared in the Sept/Oct issue of Gear Technology. Unfortunately, some readers many be unnecessarily deterred from applying the analysis to their own situations by the formidabilty of the mathematical calculations. I am making the following small suggestion concerning the evaluation of the constant terms.

The Integral Temperature Method for the evaluation of the scoring load capacity of gears is described. All necessary equations for the practical application are presented. The limit scoring temperature for any oil can be obtained from a gear scoring test.

Gear research seems to be thriving. Between September 10th and October 17th, 120 papers about gears
were presented at three conferences in Milwaukee, Boston, and Washington, to a total audience of about 400. The authors were from nine countries. Slightly more than half of the papers were prepared by authors who
live outside the US and Canada.

Tooth contact under load is an important verification of the real contact conditions of a gear pair and an
important add-on to the strength calculation according to standards such
as ISO, AGMA or DIN. The contact analysis simulates the meshing of the
two flanks over the complete meshing
cycle and is therefore able to consider
individual modifications on the flank
at each meshing position.

In the design of any new gear drive, the performance of previous similar designs is very carefully considered. In the course of evaluating one such new design, the authors were faced with the task of comparing it with two similar existing systems, both of which were operating quite successfully. A problem arose, however, when it was realized that the bending stress levels of the two baselines differed substantially. In order to investigate these differences and realistically compare them to the proposed new design, a three-dimensional finite-element method (FEM) approach was applied to all three gears.

With this issue, we're proud to present our latest milestone. The Gear Technology Buyers Guide 2003 on CD-ROM - a comprehensive snapshot of nearly 400 of the industry's suppliers - is the best directory of the gear industry available.